Update library.properties - bump version to 1.4.0

Fix high-numbered RP2350's

.github/workflows/githubci.yml

@@ -7,11 +7,11 @@ jobs:
     runs-on: ubuntu-latest
     
     steps:
-    - uses: actions/setup-python@v1
+    - uses: actions/setup-python@v4
       with:
         python-version: '3.x'
-    - uses: actions/checkout@v2
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
+    - uses: actions/checkout@v3
       with:
          repository: adafruit/ci-arduino
          path: ci
@@ -20,7 +20,7 @@ jobs:
       run: bash ci/actions_install.sh
 
     - name: test platforms
-      run: python3 ci/build_platform.py feather_m0_express_tinyusb metro_m4_tinyusb pico_rp2040_tinyusb feather_esp32s3
+      run: python3 ci/build_platform.py feather_m0_express_tinyusb metro_m4_tinyusb pico_rp2040_tinyusb feather_esp32s3 pico_rp2350_tinyusb
 
     - name: clang
       run: python3 ci/run-clang-format.py -e "ci/*" -e "bin/*" -r . 

Adafruit_NeoPXL8.cpp

@@ -6,13 +6,13 @@
  * @file Adafruit_NeoPXL8.cpp
  *
  * @mainpage 8-way concurrent DMA NeoPixel library for SAMD21, SAMD51,
- * RP2040 and ESP32S3 microcontrollers.
+ * RP2040, RP235x, and ESP32S3 microcontrollers.
  *
  * @section intro_sec Introduction
  *
  * Adafruit_NeoPXL8 is an Arduino library that leverages hardware features
  * unique to some Atmel SAMD21 and SAMD51 microcontrollers, plus the
- * Raspberry Pi RP2040 and Espressif ESP32S3 (not S2, etc.) chips, to
+ * Raspberry Pi RP2040, RP235x, and Espressif ESP32S3 (not S2, etc.) chips, to
  * communicate with large numbers of NeoPixels with very low CPU utilization
  * and without losing track of time. It was originally designed for the
  * Adafruit Feather M0 board with NeoPXL8 FeatherWing interface/adapter,
@@ -41,9 +41,9 @@
  * gamma correction. This requires inordinate RAM, and the frequent need
  * for refreshing makes it best suited for multi-core chips (e.g. RP2040).
  *
- * RP2040 support requires Philhower core (not Arduino mbed core).
- * Also on RP2040, pin numbers passed to constructor are GP## indices,
- * not necessarily the digital pin numbers silkscreened on the board.
+ * RP2040 and RP235x support requires Philhower core (not Arduino mbed core).
+ * Also on RP2040 and RP235x, pin numbers passed to constructor are GP##
+ * indices, not necessarily the digital pin numbers silkscreened on the board.
  *
  * 0/1 bit timing does not precisely match NeoPixel/WS2812/SK6812 datasheet
  * specs, but it seems to work well enough. Use at your own peril.
@@ -91,7 +91,7 @@
 // NeoPixel spec)...usually only affects the 1st pixel, subsequent pixels OK
 // due to signal reshaping through the 1st.
 
-static const int8_t defaultPins[] = {0, 1, 2, 3, 4, 5, 6, 7};
+static const int8_t defaultPins[] = NEOPXL8_DEFAULT_PINS;
 static volatile bool sending = 0;     // Set while DMA transfer is active
 static volatile uint32_t lastBitTime; // micros() when last bit issued
 
@@ -109,6 +109,9 @@ Adafruit_NeoPXL8::Adafruit_NeoPXL8(uint16_t n, int8_t *p, neoPixelType t)
 static Adafruit_NeoPXL8 *neopxl8_ptr = NULL;
 
 #if defined(ARDUINO_ARCH_RP2040)
+// note that ARDUINO_ARCH_RP2040 blocks also apply to RP235x
+
+#define DMA_IRQ_N 1 ///< Can be 0 or 1, no functional difference, 1 looks cool
 
 // PIO code. As currently written, uses 2/9 and 5/9 duty cycle for '0' and
 // '1' bits respectively. This does not match the datasheet, but works well
@@ -132,13 +135,15 @@ static const struct pio_program neopxl8_program = {
 };
 
 // Called at end of DMA transfer. Clears 'sending' flag and notes start of
-// NeoPixel latch time. Done as a callback (from the IRQ below) because
+// NeoPixel latch time. Done as a callback (from the IRQ below) because it
 // needs access to a protected NeoPXL8 member (dma_channel).
 void Adafruit_NeoPXL8::dma_callback() {
-  dma_hw->ints0 = 1u << dma_channel; // Clear IRQ
+  if (dma_irqn_get_channel_status(DMA_IRQ_N, dma_channel)) {
+    dma_irqn_acknowledge_channel(DMA_IRQ_N, dma_channel); // Clear IRQ
     lastBitTime = micros();
     sending = 0;
   }
+}
 
 static void dma_finish_irq(void) {
   if (neopxl8_ptr) {
@@ -269,13 +274,18 @@ static void dmaCallback(Adafruit_ZeroDMA *dma) {
 
 Adafruit_NeoPXL8::~Adafruit_NeoPXL8() {
 #if defined(ARDUINO_ARCH_RP2040)
+  pio_sm_set_enabled(pio, sm, false);
+  pio_remove_program(pio, &neopxl8_program, offset);
+  pio_sm_unclaim(pio, sm);
   dma_channel_abort(dma_channel);
+  dma_channel_unclaim(dma_channel);
   if (dmaBuf[0])
     free(dmaBuf[0]);
+  irq_remove_handler(DMA_IRQ_N == 0 ? DMA_IRQ_0 : DMA_IRQ_1, dma_finish_irq);
 #elif defined(CONFIG_IDF_TARGET_ESP32S3)
   gdma_reset(dma_chan);
   if (allocAddr)
-    free(allocAddr);
+    heap_caps_free(allocAddr);
 #else
   dma.abort();
   if (allocAddr)
@@ -284,11 +294,7 @@ Adafruit_NeoPXL8::~Adafruit_NeoPXL8() {
   neopxl8_ptr = NULL;
 }
 
-#if defined(ARDUINO_ARCH_RP2040)
-bool Adafruit_NeoPXL8::begin(bool dbuf, PIO pio_instance) {
-#else
 bool Adafruit_NeoPXL8::begin(bool dbuf) {
-#endif
   Adafruit_NeoPixel::begin(); // Call base class begin() function 1st
   if (pixels) {               // Successful malloc of NeoPixel buffer?
     uint8_t bytesPerPixel = (wOffset == rOffset) ? 3 : 4;
@@ -298,9 +304,6 @@ bool Adafruit_NeoPXL8::begin(bool dbuf) {
     neopxl8_ptr = this; // Save object pointer for interrupt
 
 #if defined(ARDUINO_ARCH_RP2040)
-
-    pio = pio_instance;
-
     // Validate pins, must be within any 8 consecutive GPIO bits
     int16_t least_pin = 0x7FFF, most_pin = -1;
     for (uint8_t i = 0; i < 8; i++) {
@@ -321,23 +324,20 @@ bool Adafruit_NeoPXL8::begin(bool dbuf) {
       // If no double buffering, point both to same space
       dmaBuf[1] = dbuf ? &dmaBuf[0][buf_size] : dmaBuf[0];
 
-      // Set up PIO outputs
-      uint32_t pindir_mask = 0;
-      for (uint8_t i = 0; i < 8; i++) {
-        if (pins[i] >= 0) {
-          pio_gpio_init(pio, pins[i]);
-          pindir_mask = 1 << pins[i];
-          bitmask[i] = 1 << (pins[i] - least_pin);
-        }
-      }
-      // Func not working? Or using it wrong?
-      // pio_sm_set_pindirs_with_mask(pio, sm, pindir_mask, pindir_mask);
-      // For now, set all 8 as outputs, even if in-betweens are skipped
-      pio_sm_set_consecutive_pindirs(pio, sm, least_pin, 8, true);
-
       // Set up PIO code & clock
-      uint offset = pio_add_program(pio, &neopxl8_program);
-      sm = pio_claim_unused_sm(pio, true); // 0-3
+      // Find a PIO with enough available space in its instruction memory
+      pio = NULL;
+
+      if (!pio_claim_free_sm_and_add_program_for_gpio_range(
+              &neopxl8_program, &pio, &sm, &offset, least_pin, 8, true)) {
+        pio = NULL;
+        sm = -1;
+        offset = 0;
+        return false; // No PIO available
+      }
+
+      // offset = pio_add_program(pio, &neopxl8_program);
+      // sm = pio_claim_unused_sm(pio, true); // 0-3
       pio_sm_config conf = pio_get_default_sm_config();
       conf.pinctrl = 0; // SDK fails to set this
       sm_config_set_wrap(&conf, offset, offset + neopxl8_program.length - 1);
@@ -350,6 +350,21 @@ bool Adafruit_NeoPXL8::begin(bool dbuf) {
       pio_sm_init(pio, sm, offset, &conf);
       pio_sm_set_enabled(pio, sm, true);
 
+      // Set up PIO outputs
+      uint32_t pindir_mask = 0;
+      for (uint8_t i = 0; i < 8; i++) {
+        if (pins[i] >= 0) {
+          pio_gpio_init(pio, pins[i]);
+          gpio_set_drive_strength(pins[i], GPIO_DRIVE_STRENGTH_2MA);
+          pindir_mask = 1 << pins[i];
+          bitmask[i] = 1 << (pins[i] - least_pin);
+        }
+      }
+      // Func not working? Or using it wrong?
+      // pio_sm_set_pindirs_with_mask(pio, sm, pindir_mask, pindir_mask);
+      // For now, set all 8 as outputs, even if in-betweens are skipped
+      pio_sm_set_consecutive_pindirs(pio, sm, least_pin, 8, true);
+
       // Set up DMA transfer
       dma_channel = dma_claim_unused_channel(false); // Don't panic
 
@@ -364,9 +379,15 @@ bool Adafruit_NeoPXL8::begin(bool dbuf) {
                             dmaBuf[dbuf_index], // src
                             buf_size, false);
       // Set up end-of-DMA interrupt
-      irq_set_exclusive_handler(DMA_IRQ_0, dma_finish_irq);
+      irq_add_shared_handler(DMA_IRQ_N == 0 ? DMA_IRQ_0 : DMA_IRQ_1,
+                             dma_finish_irq,
+                             PICO_SHARED_IRQ_HANDLER_DEFAULT_ORDER_PRIORITY);
+#if (DMA_IRQ_N == 0)
       dma_channel_set_irq0_enabled(dma_channel, true);
-      irq_set_enabled(DMA_IRQ_0, true);
+#else
+      dma_channel_set_irq1_enabled(dma_channel, true);
+#endif
+      irq_set_enabled(DMA_IRQ_N == 0 ? DMA_IRQ_0 : DMA_IRQ_1, true);
 
       return true; // Success!
     }
@@ -379,13 +400,14 @@ bool Adafruit_NeoPXL8::begin(bool dbuf) {
     uint32_t alloc_size =
         num_desc * sizeof(dma_descriptor_t) + (dbuf ? buf_size * 2 : buf_size);
 
-    if ((allocAddr = (uint8_t *)malloc(alloc_size))) {
+    if ((allocAddr = (uint8_t *)heap_caps_malloc(
+             alloc_size, MALLOC_CAP_DMA | MALLOC_CAP_8BIT))) {
 
       // Find first 32-bit aligned address following descriptor list
       alignedAddr[0] =
           (uint32_t
-               *)((uint32_t)(
-                      &allocAddr[num_desc * sizeof(dma_descriptor_t) + 3]) &
+               *)((uint32_t)(&allocAddr[num_desc * sizeof(dma_descriptor_t) +
+                                        3]) &
                   ~3);
       dmaBuf[0] = (uint8_t *)alignedAddr[0];
 
@@ -488,7 +510,7 @@ bool Adafruit_NeoPXL8::begin(bool dbuf) {
     dbuf = false;
 
     uint32_t buf_size = numLEDs * bytesPerPixel * 3 + EXTRASTARTBYTES + 3;
-  uint32_t alloc_size = dbuf ? buf_size * 2 : buf_size;
+    // uint32_t alloc_size = dbuf ? buf_size * 2 : buf_size;
 
     if ((allocAddr = (uint8_t *)malloc(buf_size))) {
       int i;
@@ -507,7 +529,8 @@ bool Adafruit_NeoPXL8::begin(bool dbuf) {
 
       if (dbuf) {
         alignedAddr[1] =
-          (uint32_t *)((uint32_t)(&allocAddr[buf_size + EXTRASTARTBYTES + 3]) &
+            (uint32_t
+                 *)((uint32_t)(&allocAddr[buf_size + EXTRASTARTBYTES + 3]) &
                     ~3);
         dmaBuf[1] = (uint8_t *)alignedAddr[1] - EXTRASTARTBYTES;
         memset(dmaBuf[1], 0, EXTRASTARTBYTES);
@@ -553,7 +576,8 @@ bool Adafruit_NeoPXL8::begin(bool dbuf) {
         ; // Wait for enable
 #else
       // Enable GCLK for TCC0
-    GCLK->CLKCTRL.reg = (uint16_t)(GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK0 |
+      GCLK->CLKCTRL.reg =
+          (uint16_t)(GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK0 |
                      GCLK_CLKCTRL_ID(GCM_TCC0_TCC1));
       while (GCLK->STATUS.bit.SYNCBUSY == 1)
         ;
@@ -834,13 +858,7 @@ Adafruit_NeoPXL8HDR::~Adafruit_NeoPXL8HDR() {
     free(pixel_buf[0]);
 }
 
-#if defined(ARDUINO_ARCH_RP2040)
-bool Adafruit_NeoPXL8HDR::begin(bool blend, uint8_t bits, bool dbuf,
-                                PIO pio_instance) {
-#else
 bool Adafruit_NeoPXL8HDR::begin(bool blend, uint8_t bits, bool dbuf) {
-#endif
-
   // If blend flag is set, allocate 3X pixel buffers, else 2X (for
   // temporal dithering only). Result is the buffer size in 16-bit
   // words (not bytes).
@@ -851,15 +869,12 @@ bool Adafruit_NeoPXL8HDR::begin(bool blend, uint8_t bits, bool dbuf) {
   if ((pixel_buf[0] = (uint16_t *)malloc(buf_size * sizeof(uint16_t)))) {
     if ((dither_table =
              (uint16_t *)malloc((1 << dither_bits) * sizeof(uint16_t)))) {
-#if defined(ARDUINO_ARCH_RP2040)
-      if (Adafruit_NeoPXL8::begin(dbuf, pio_instance)) {
-        mutex_init(&mutex);
-#else
       if (Adafruit_NeoPXL8::begin(dbuf)) {
-#if defined(CONFIG_IDF_TARGET_ESP32S3)
+#if defined(ARDUINO_ARCH_RP2040)
+        mutex_init(&mutex);
+#elif defined(CONFIG_IDF_TARGET_ESP32S3)
         mutex = xSemaphoreCreateMutex();
-#endif // end ESP32S3
-#endif // end !RP2040
+#endif // end ESP32S3/RP2040
 
         // All allocations & initializations were successful.
         // Generate bit-flip table for ordered dithering...
@@ -1278,7 +1293,7 @@ DMA-capable peripherals is exploited for byte-wide concurrent output
 (specifically the TCC0 pattern generator, which is normally used for
 motor control or some such). Although SAMD51 does have PORT DMA, the
 pattern generator approach is used there regardless, so similar code
-can be used for both chips. On RP2040, PIO code is used.
+can be used for both chips. On RP2040 and RP235x, PIO code is used.
 
 To issue 8 bits in parallel, all bytes of NeoPixel data must be "turned
 sideways" in RAM so all the bit 7's are issued concurrently, then all

Adafruit_NeoPXL8.h

@@ -5,8 +5,8 @@
 /*!
  * @file Adafruit_NeoPXL8.h
  *
- * 8-way concurrent DMA NeoPixel library for SAMD21, SAMD51, RP2040, and
- * ESP32S3 microcontrollers.
+ * 8-way concurrent DMA NeoPixel library for SAMD21, SAMD51, RP2040, RP235x,
+ * and ESP32S3 microcontrollers.
  *
  * Adafruit invests time and resources providing this open source code,
  * please support Adafruit and open-source hardware by purchasing
@@ -63,8 +63,8 @@ public:
             mind that this will always still use the same amount of memory
             as 8-way output. If unspecified (or if NULL is passed), a
             default 8-pin setup will be used (see example sketch).
-            On RP2040, these are GP## numbers, not necessarily the digital
-            pin numbers silkscreened on the board.
+            On RP2040 and RP235x, these are GP## numbers, not necessarily the
+            digital pin numbers silkscreened on the board.
     @param  t
             NeoPixel color data order, same as in Adafruit_NeoPixel library
             (optional, default is GRB).
@@ -81,11 +81,7 @@ public:
                   NeoPXL8HDR's use. Currently ignored on SAMD.
     @return true on successful alloc/init, false otherwise.
   */
-#if defined(ARDUINO_ARCH_RP2040)
-  bool begin(bool dbuf = false, PIO pio_instance = pio0);
-#else
   bool begin(bool dbuf = false);
-#endif
 
   /*!
     @brief  Process and issue new data to the NeoPixel strands.
@@ -175,8 +171,9 @@ public:
 
 protected:
 #if defined(ARDUINO_ARCH_RP2040)
-  PIO pio;                       ///< PIO peripheral
-  uint8_t sm;                    ///< State machine #
+  PIO pio = NULL; ///< PIO peripheral
+  uint sm = -1;   ///< State machine #
+  uint offset = 0;
   int dma_channel;               ///< DMA channel #
   dma_channel_config dma_config; ///< DMA configuration
 #elif defined(CONFIG_IDF_TARGET_ESP32S3)
@@ -206,7 +203,7 @@ protected:
          additions for 16-bits-per-channel color, temporal dithering,
          frame blending and gamma correction. This requires inordinate RAM,
          and the frequent need for refreshing makes it best suited for
-         multi-core chips (e.g. RP2040).
+         multi-core chips (e.g. RP2040, RP235x).
 */
 class Adafruit_NeoPXL8HDR : public Adafruit_NeoPXL8 {
 
@@ -226,8 +223,8 @@ public:
             mind that this will always still use the same amount of memory
             as 8-way output. If unspecified (or if NULL is passed), a
             default 8-pin setup will be used (see example sketch).
-            On RP2040, these are GP## numbers, not necessarily the digital
-            pin numbers silkscreened on the board.
+            On RP2040 and RP235x, these are GP## numbers, not necessarily the
+            digital pin numbers silkscreened on the board.
     @param  t
             NeoPixel color data order, same as in Adafruit_NeoPixel library
             (optional, default is GRB).
@@ -241,7 +238,7 @@ public:
                    refresh() function between show() calls (uses more RAM).
                    If false (default), no blending. This is useful ONLY if
                    sketch can devote time to many refresh() calls, e.g. on
-                   multicore RP2040.
+                   multicore RP2040 or RP235x.
     @param  bits   Number of bits for temporal dithering, 0-8. Higher values
                    provide more intermediate shades but slower refresh;
                    dither becomes more apparent. Default is 4, providing
@@ -252,12 +249,7 @@ public:
                    others just waste RAM. Currently ignored on SAMD.
     @return true on successful alloc/init, false otherwise.
   */
-#if defined(ARDUINO_ARCH_RP2040)
-  bool begin(bool blend = false, uint8_t bits = 4, bool dbuf = false,
-             PIO pio_instance = pio0);
-#else
   bool begin(bool blend = false, uint8_t bits = 4, bool dbuf = false);
-#endif
 
   /*!
     @brief  Set peak output brightness for all channels (RGB and W if
@@ -505,13 +497,19 @@ public:
   /*!
     @brief   Query overall display refresh rate in frames-per-second.
              This is only an estimate and requires a moment to stabilize;
-             will initially be 0. It's really only helpful on RP2040 where
-             the refresh loop runs full-tilt on its own core; on SAMD,
+             will initially be 0. It's really only helpful on RP2040 and RP235x
+             where the refresh loop runs full-tilt on its own core; on SAMD,
              refresh is handled with a fixed timer interrupt.
     @return  Integer frames (pixel refreshes) per second.
   */
   uint32_t getFPS(void) const { return fps; }
 
+  /*!
+    @brief   Fill the whole NeoPixel strip with 0 / black / off.
+    @note    Overloaded from Adafruit_NeoPixel because stored different here.
+  */
+  void clear(void) { memset(pixel_buf[2], 0, numBytes * sizeof(uint16_t)); }
+
 protected:
   /*!
     @brief  Recalculate the tables used for gamma correction and temporal
@@ -539,4 +537,35 @@ protected:
 #endif
 };
 
+// The DEFAULT_PINS macros provide shortcuts for the most commonly-used pin
+// lists on certain boards. For example, with a Feather M0, the default list
+// will match an unaltered, factory-fresh NeoPXL8 FeatherWing M0. If ANY pins
+// are changed on the FeatherWing, or if using a different pin sequence than
+// these defaults, a user sketch must provide its own correct pin list.
+// These may work for sloppy quick code but are NOT true in all situations!
+#if defined(ARDUINO_ADAFRUIT_FEATHER_RP2040_SCORPIO)
+#define NEOPXL8_DEFAULT_PINS                                                   \
+  { 16, 17, 18, 19, 20, 21, 22, 23 }
+#elif defined(ADAFRUIT_FEATHER_M0) || defined(ARDUINO_SAMD_FEATHER_M0_EXPRESS)
+#define NEOPXL8_DEFAULT_PINS                                                   \
+  { PIN_SERIAL1_RX, PIN_SERIAL1_TX, MISO, 13, 5, SDA, A4, A3 }
+#elif defined(ADAFRUIT_FEATHER_M4_EXPRESS) ||                                  \
+    defined(ARDUINO_ADAFRUIT_FEATHER_ESP32S3) ||                               \
+    defined(ARDUINO_ADAFRUIT_FEATHER_ESP32S3_NOPSRAM)
+#define NEOPXL8_DEFAULT_PINS                                                   \
+  { SCK, 5, 9, 6, 13, 12, 11, 10 }
+#elif defined(ADAFRUIT_METRO_M4_EXPRESS)
+#define NEOPXL8_DEFAULT_PINS                                                   \
+  { 7, 4, 5, 6, 3, 2, 10, 11 }
+#elif defined(ADAFRUIT_GRAND_CENTRAL_M4)
+#define NEOPXL8_DEFAULT_PINS                                                   \
+  { 30, 31, 32, 33, 36, 37, 34, 35 }
+#elif defined(ARDUINO_ADAFRUIT_FEATHER_RP2040)
+#define NEOPXL8_DEFAULT_PINS                                                   \
+  { 6, 7, 9, 8, 13, 12, 11, 10 }
+#else
+#define NEOPXL8_DEFAULT_PINS                                                   \
+  { 0, 1, 2, 3, 4, 5, 6, 7 } ///< Generic pin list
+#endif
+
 #endif // _ADAFRUIT_NEOPXL8_H_

README.md

@@ -1,5 +1,5 @@
 # Adafruit_NeoPXL8
-DMA-driven 8-way concurrent NeoPixel driver for SAMD21 (M0+), SAMD51 (M4), RP2040 and ESP32S3 microcontrollers. Requires latest Adafruit_NeoPixel and Adafruit_ZeroDMA libraries.
+DMA-driven 8-way concurrent NeoPixel driver for SAMD21 (M0+), SAMD51 (M4), RP2040, RP235x, and ESP32S3 microcontrollers. Requires latest Adafruit_NeoPixel and Adafruit_ZeroDMA libraries.
 
 (Pronounced "NeoPixelate")
 
@@ -42,12 +42,12 @@ Other boards (such as Grand Central) have an altogether different pinout. See th
 
 Pin MUXing is a hairy thing and over time we'll try to build up some ready-to-use examples for different boards and peripherals. You can also try picking your way through the SAMD21/51 datasheet or the NeoPXL8 source code for pin/peripheral assignments.
 
-On RP2040 boards, the pins can be within any 8-pin range (e.g. 0-7, or 4-11, etc.). If using fewer than 8 outputs, they do not need to be contiguous, but the lowest and highest pin number must still be within 8-pin range.
+On RP2040 and RP235x boards, the pins can be within any 8-pin range (e.g. 0-7, or 4-11, etc.). If using fewer than 8 outputs, they do not need to be contiguous, but the lowest and highest pin number must still be within 8-pin range.
 
 On ESP32S3 boards, go wild...there are no pin restrictions.
 
 ## NeoPXL8HDR
 
-Adafruit_NeoPXL8HDR is a subclass of Adafruit_NeoPXL8 with additions for 16-bit color, temporal dithering, gamma correction and frame blending. This requires inordinate RAM, and the need for frequent refreshing makes it best suited for multi-core chips (e.g. RP2040).
+Adafruit_NeoPXL8HDR is a subclass of Adafruit_NeoPXL8 with additions for 16-bit color, temporal dithering, gamma correction and frame blending. This requires inordinate RAM, and the need for frequent refreshing makes it best suited for multi-core chips (e.g. RP2040 and RP235x).
 
 See examples/NeoPXL8HDR/strandtest for use.

examples/NeoPXL8/PlasmaAnimation/PlasmaAnimation.ino

@@ -78,7 +78,5 @@ void loop() {
 }
 
 inline uint8_t fastCosineCalc( uint16_t preWrapVal) {
-  uint8_t wrapVal = (preWrapVal % 255);
-  if (wrapVal<0) wrapVal=255+wrapVal;
-  return (pgm_read_byte_near(cos_wave+wrapVal));
+  return (pgm_read_byte_near(cos_wave + (preWrapVal & 255)));
 }

examples/NeoPXL8/VideoMSC/VideoMSC.ino

@@ -1,30 +1,33 @@
+// This sketch is Just Too Much for SAMD21 (M0) boards.
+// Recommend RP2040/SCORPIO, M4 or ESP32-S3.
+
 // FIRST TIME HERE? START WITH THE NEOPXL8 strandtest EXAMPLE INSTEAD!
 // That code explains and helps troubshoot wiring and NeoPixel color format.
 
 // This is a companion to "move2msc" in the extras/Processing folder.
 // It plays preconverted videos from the on-board flash filesystem.
 
+#include "SdFat_Adafruit_Fork.h"
 #include <Adafruit_NeoPXL8.h>
+#include <Adafruit_CPFS.h> // For accessing CIRCUITPY drive
+#define ARDUINOJSON_ENABLE_COMMENTS 1
+#include <ArduinoJson.h>
 
-// CHANGE these to match your strandtest findings or this WILL NOT WORK:
-
-int8_t pins[8] = { 6, 7, 9, 8, 13, 12, 11, 10 };
-#define COLOR_ORDER NEO_GRB
-
-#define SYNC_PIN -1 // -1 = not used
-
-// This example is minimally adapted from one in PJRC's OctoWS2811 Library:
+// This example is adapted from one in PJRC's OctoWS2811 Library. Original
+// comments appear first, and Adafruit_NeoPXL8 changes follow that. Any
+// original comments about "SD card" now apply to a board's CIRCUITPY flash
+// filesystem instead.
 
 /*  OctoWS2811 VideoSDcard.ino - Video on LEDs, played from SD Card
     http://www.pjrc.com/teensy/td_libs_OctoWS2811.html
     Copyright (c) 2014 Paul Stoffregen, PJRC.COM, LLC
 
-    Permission is hereby granted, free of charge, to any person obtaining a copy
-    of this software and associated documentation files (the "Software"), to deal
-    in the Software without restriction, including without limitation the rights
-    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-    copies of the Software, and to permit persons to whom the Software is
-    furnished to do so, subject to the following conditions:
+    Permission is hereby granted, free of charge, to any person obtaining a
+    copy of this software and associated documentation files (the "Software"),
+    to deal in the Software without restriction, including without limitation
+    the rights to use, copy, modify, merge, publish, distribute, sublicense,
+    and/or sell copies of the Software, and to permit persons to whom the
+    Software is furnished to do so, subject to the following conditions:
 
     The above copyright notice and this permission notice shall be included in
     all copies or substantial portions of the Software.
@@ -33,9 +36,9 @@ int8_t pins[8] = { 6, 7, 9, 8, 13, 12, 11, 10 };
     IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
     AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-    THE SOFTWARE.
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+    DEALINGS IN THE SOFTWARE.
 
 Update: The programs to prepare the SD card video file have moved to "extras"
 https://github.com/PaulStoffregen/OctoWS2811/tree/master/extras
@@ -69,71 +72,139 @@ https://github.com/PaulStoffregen/OctoWS2811/tree/master/extras
     pin 13: SD Card, SCLK
 */
 
-#include "SPI.h"
-#include "SdFat.h"
-#include "Adafruit_SPIFlash.h"
-#include "Adafruit_TinyUSB.h"
+/*
+    ADAFRUIT_NEOPXL8 UPDATE:
 
-#define LED_WIDTH    30   // number of LEDs horizontally
-#define LED_HEIGHT   16   // number of LEDs vertically (must be multiple of 8)
-#define LED_LAYOUT   1    // 0 = even rows left->right, 1 = even rows right->left
+    Aside from changes to convert from OctoWS2811 to Adafruit_NeoPXL8, the
+    big drastic change here is to eliminate many compile-time constants and
+    instead place these in a JSON configuration file on a board's CIRCUITPY
+    flash filesystem (though this is Arduino code, we can still make use of
+    that drive), and declare the LEDs at run time. Other than those
+    alterations, the code is minimally changed. Paul did the real work. :)
+
+    Run-time configuration is stored in CIRCUITPY/neopxl8.cfg and resembles:
+
+    {
+      "pins" : [ 16, 17, 18, 19, 20, 21, 22, 23 ],
+      "order" : "GRB",
+      "led_width" : 30,
+      "led_height" : 16,
+      "led_layout" : 0
+    }
+
+    If this file is missing, or if any individual elements are unspecified,
+    defaults will be used (these are noted later in the code). It's possible,
+    likely even, that there will be additional elements in this file...
+    for example, some NeoPXL8 code might use a single "length" value rather
+    than width/height, as not all projects are using a grid. Be warned that
+    JSON is highly picky and even a single missing or excess comma will stop
+    everything, so read through it very carefully if encountering an error.
+*/
 
 #define FILENAME "mymovie.bin"
 
-const int ledsPerStrip = LED_WIDTH * LED_HEIGHT / 8;
-uint8_t imageBuffer[LED_WIDTH * LED_HEIGHT * 3];
-uint32_t timeOfLastFrame = 0;
-bool playing = false;
+// In original code, these were constants LED_WIDTH, LED_HEIGHT and
+// LED_LAYOUT. Values here are defaults but can override in config file.
+// led_height MUST be a multiple of 8. When 16, 24, 32 are used, each strip
+// spans 2, 3, 4 rows. led_layout indicates how strips are arranged.
+uint16_t led_width  = 30; // Number of LEDs horizontally
+uint16_t led_height = 16; // Number of LEDs vertically
+uint8_t  led_layout = 0;  // 0 = even rows left->right, 1 = right->left
 
-Adafruit_NeoPXL8 leds(ledsPerStrip, pins, COLOR_ORDER);
-
-// From tinyUSB msc_external_flash example
-#if defined(ARDUINO_ARCH_RP2040)
-  Adafruit_FlashTransport_RP2040 flashTransport;
-#elif defined(CONFIG_IDF_TARGET_ESP32S3)
-  Adafruit_FlashTransport_ESP32 flashTransport;
-#else
-  #if defined(EXTERNAL_FLASH_USE_QSPI)
-    Adafruit_FlashTransport_QSPI flashTransport;
-  #elif defined(EXTERNAL_FLASH_USE_SPI)
-    Adafruit_FlashTransport_SPI flashTransport(EXTERNAL_FLASH_USE_CS, EXTERNAL_FLASH_USE_SPI);
-  #else
-    #error No QSPI/SPI flash are defined on your board variant.h !
-  #endif
-#endif
-
-Adafruit_SPIFlash flash(&flashTransport);
-
-FatFileSystem fatfs; // file system object from SdFat
 FatFile file;
-Adafruit_USBD_MSC usb_msc; // USB Mass Storage object
-bool fs_changed = true; // Set to true when PC write to flash
+bool playing = false;
+uint32_t timeOfLastFrame = 0;
+uint8_t *imageBuffer;     // LED data from filesystem is staged here
+uint32_t imageBufferSize; // Size (in bytes) of imageBuffer
+
+Adafruit_NeoPXL8 *leds; // NeoPXL8 object is allocated after reading config
+
+void error_handler(const char *message, uint16_t speed) {
+  Serial.print("Error: ");
+  Serial.println(message);
+  if (speed) { // Fatal error, blink LED
+    pinMode(LED_BUILTIN, OUTPUT);
+    for (;;) {
+      digitalWrite(LED_BUILTIN, (millis() / speed) & 1);
+      yield(); // Keep filesystem accessible for editing
+    }
+  } else { // Not fatal, just show message
+    Serial.println("Continuing with defaults");
+  }
+}
+
 
 void setup() {
-  // Flash setup from tinyUSB msc_external_flash example
-  flash.begin();
-  // Set disk vendor id, product id and revision with string up to 8, 16, 4 characters respectively
-  usb_msc.setID("Adafruit", "External Flash", "1.0");
-  usb_msc.setReadWriteCallback(msc_read_cb, msc_write_cb, msc_flush_cb); // Set callback
-  // Set disk size, block size should be 512 regardless of spi flash page size
-  usb_msc.setCapacity(flash.size()/512, 512);
-  usb_msc.setUnitReady(true); // MSC is ready for read/write
-  usb_msc.begin();
-  fatfs.begin(&flash); // Init file system on the flash
+  // CHANGE these to match your strandtest findings (or use .cfg file):
+  int8_t pins[8] = NEOPXL8_DEFAULT_PINS;
+  uint16_t order = NEO_GRB;
 
+  // Start the CIRCUITPY flash filesystem first. Very important!
+  FatVolume *fs = Adafruit_CPFS::begin();
+
+  // Start Serial AFTER FFS begin, else CIRCUITPY won't show on computer.
   Serial.begin(115200);
   //while(!Serial);
-  delay(50);
+  delay(1000);
+  Serial.setTimeout(50);
   Serial.println("VideoMSC");
 
-  if (!leds.begin()) {
-    pinMode(LED_BUILTIN, OUTPUT);
-    for (;;) digitalWrite(LED_BUILTIN, (millis() / 500) & 1);
+  if (fs == NULL) {
+    error_handler("Can't access CIRCUITPY drive", 0);
+  } else {
+    StaticJsonDocument<1024> doc;
+    DeserializationError error;
+
+    // Open NeoPXL8 configuration file and attempt to decode JSON data within.
+    if ((file = fs->open("neopxl8.cfg", FILE_READ))) {
+      error = deserializeJson(doc, file);
+      file.close();
+    } else {
+      error_handler("neopxl8.cfg not found", 0);
     }
-  leds.show();
+
+    if(error) {
+      error_handler("neopxl8.cfg syntax error", 0);
+      Serial.print("JSON error: ");
+      Serial.println(error.c_str());
+    } else {
+      // Config is valid, override defaults in program variables...
+
+      JsonVariant v = doc["pins"];
+      if (v.is<JsonArray>()) {
+        uint8_t n = v.size() < 8 ? v.size() : 8;
+        for (uint8_t i = 0; i < n; i++)
+          pins[i] = v[i].as<int>();
+      }
+
+      v = doc["order"];
+      if (v.is<const char *>()) order = Adafruit_NeoPixel::str2order(v);
+
+      led_width  = doc["led_width"]  | led_width;
+      led_height = doc["led_height"] | led_height;
+      led_layout = doc["led_layout"] | led_layout;
+    } // end JSON OK
+  } // end filesystem OK
+
+  // Any errors after this point are unrecoverable and program will stop.
+
+  // Dynamically allocate NeoPXL8 object
+  leds = new Adafruit_NeoPXL8(led_width * led_height / 8, pins, order);
+  if (leds == NULL) error_handler("NeoPXL8 allocation", 100);
+
+  // Allocate imageBuffer
+  imageBufferSize = led_width * led_height * 3;
+  imageBuffer = (uint8_t *)malloc(imageBufferSize);
+  if (imageBuffer == NULL) error_handler("Image buffer allocation", 200);
+
+  if (!leds->begin()) error_handler("NeoPXL8 begin() failed", 500);
+
+  // At this point, everything but input file is ready to go!
+
+  leds->show(); // LEDs off ASAP
 
   bool status = file.open(FILENAME, O_RDONLY);
-  if (!status) stopWithErrorMessage("Could not read " FILENAME);
+  if (!status) error_handler("Can't open movie .bin file", 1000);
   Serial.println("File opened");
   playing = true;
   timeOfLastFrame = 0;
@@ -196,8 +267,8 @@ void loop()
         unsigned int usec = header[3] | (header[4] << 8);
         unsigned int readsize = size;
 	      //Serial.printf("v: %u %u\n", size, usec);
-        if (readsize > sizeof(imageBuffer)) {
-          readsize = sizeof(imageBuffer);
+        if (readsize > imageBufferSize) {
+          readsize = imageBufferSize;
         }
         if (sd_card_read(imageBuffer, readsize)) {
           uint32_t now;
@@ -268,53 +339,29 @@ void error(const char *str)
   playing = false;
 }
 
-// when an error happens during setup, give up and print a message
-// to the serial monitor.
-void stopWithErrorMessage(const char *str)
-{
-  while (1) {
-    Serial.println(str);
-    delay(1000);
-  }
-}
-
 void convert_and_show() {
   uint8_t *ptr = imageBuffer;
-  for (int y=0; y<LED_HEIGHT; y++) {
-    for (int x=0; x<LED_WIDTH; x++) {
-      int pixelIndex;
-#if (LED_LAYOUT == 0)
-      // Always left-to-right
-      pixelIndex = y * LED_WIDTH + x;
-#else
-      // Even rows are left-to-right, odd are right-to-left
-      if (y & 1) {
-        pixelIndex = (y + 1) * LED_WIDTH - 1 - x;
+  if (led_layout == 0) {
+    for (int y=0; y<led_height; y++) {
+      for (int x=0; x<led_width; x++) {
+        int pixelIndex = y * led_width + x; // Always left-to-right
+        uint8_t r = leds->gamma8(*ptr++);
+        uint8_t g = leds->gamma8(*ptr++);
+        uint8_t b = leds->gamma8(*ptr++);
+        leds->setPixelColor(pixelIndex, r, g, b);
+      }
+    }
   } else {
-        pixelIndex = y * LED_WIDTH + x;
-      }
-#endif
-      uint8_t r = leds.gamma8(*ptr++);
-      uint8_t g = leds.gamma8(*ptr++);
-      uint8_t b = leds.gamma8(*ptr++);
-      leds.setPixelColor(pixelIndex, r, g, b);
+    for (int y=0; y<led_height; y++) {
+      for (int x=0; x<led_width; x++) {
+        // Even rows are left-to-right, odd are right-to-left
+        int pixelIndex = (y & 1) ? (y + 1) * led_width - 1 - x : y * led_width + x;
+        uint8_t r = leds->gamma8(*ptr++);
+        uint8_t g = leds->gamma8(*ptr++);
+        uint8_t b = leds->gamma8(*ptr++);
+        leds->setPixelColor(pixelIndex, r, g, b);
       }
     }
-  leds.show();
   }
-
-// More code from tinyUSB msc_external_flash example; commented there
-
-int32_t msc_read_cb (uint32_t lba, void* buffer, uint32_t bufsize) {
-  return flash.readBlocks(lba, (uint8_t*) buffer, bufsize/512) ? bufsize : -1;
-}
-
-int32_t msc_write_cb (uint32_t lba, uint8_t* buffer, uint32_t bufsize) {
-  return flash.writeBlocks(lba, buffer, bufsize/512) ? bufsize : -1;
-}
-
-void msc_flush_cb (void) {
-  flash.syncBlocks();
-  fatfs.cacheClear();
-  fs_changed = true;
+  leds->show();
 }

examples/NeoPXL8/VideoSerial/VideoSerial.ino

@@ -1,29 +1,30 @@
+// This sketch is Just Too Much for SAMD21 (M0) boards.
+// Recommend RP2040/SCORPIO, M4 or ESP32-S3.
+
 // FIRST TIME HERE? START WITH THE NEOPXL8 strandtest EXAMPLE INSTEAD!
 // That code explains and helps troubshoot wiring and NeoPixel color format.
 
 // This is a companion to "move2serial" in the extras/Processing folder.
 
+#include "SdFat_Adafruit_Fork.h"
 #include <Adafruit_NeoPXL8.h>
+#include <Adafruit_CPFS.h> // For accessing CIRCUITPY drive
+#define ARDUINOJSON_ENABLE_COMMENTS 1
+#include <ArduinoJson.h>
 
-// CHANGE these to match your strandtest findings or this WILL NOT WORK:
-
-int8_t pins[8] = { 6, 7, 9, 8, 13, 12, 11, 10 };
-#define COLOR_ORDER NEO_GRB
-
-#define SYNC_PIN -1 // -1 = not used
-
-// This example is minimally adapted from one in PJRC's OctoWS2811 Library:
+// This example is adapted from one in PJRC's OctoWS2811 Library. Original
+// comments appear first, and Adafruit_NeoPXL8 changes follow that.
 
 /*  OctoWS2811 VideoDisplay.ino - Video on LEDs, from a PC, Mac, Raspberry Pi
     http://www.pjrc.com/teensy/td_libs_OctoWS2811.html
     Copyright (c) 2013 Paul Stoffregen, PJRC.COM, LLC
 
-    Permission is hereby granted, free of charge, to any person obtaining a copy
-    of this software and associated documentation files (the "Software"), to deal
-    in the Software without restriction, including without limitation the rights
-    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-    copies of the Software, and to permit persons to whom the Software is
-    furnished to do so, subject to the following conditions:
+    Permission is hereby granted, free of charge, to any person obtaining a
+    copy of this software and associated documentation files (the "Software"),
+    to deal in the Software without restriction, including without limitation
+    the rights to use, copy, modify, merge, publish, distribute, sublicense,
+    and/or sell copies of the Software, and to permit persons to whom the
+    Software is furnished to do so, subject to the following conditions:
 
     The above copyright notice and this permission notice shall be included in
     all copies or substantial portions of the Software.
@@ -32,9 +33,9 @@ int8_t pins[8] = { 6, 7, 9, 8, 13, 12, 11, 10 };
     IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
     AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-    THE SOFTWARE.
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+    DEALINGS IN THE SOFTWARE.
 
 Update: The movie2serial program which transmit data has moved to "extras"
 https://github.com/PaulStoffregen/OctoWS2811/tree/master/extras
@@ -74,53 +75,160 @@ https://github.com/PaulStoffregen/OctoWS2811/tree/master/extras
     ports on the same motherboard, may give poor performance.
 */
 
-// The actual arrangement of the LEDs connected to this Teensy 3.0 board.
-// LED_HEIGHT *must* be a multiple of 8.  When 16, 24, 32 are used, each
-// strip spans 2, 3, 4 rows.  LED_LAYOUT indicates the direction the strips
-// are arranged.  If 0, each strip begins on the left for its first row,
-// then goes right to left for its second row, then left to right,
-// zig-zagging for each successive row.
-#define LED_WIDTH      30   // number of LEDs horizontally
-#define LED_HEIGHT     16   // number of LEDs vertically (must be multiple of 8)
-#define LED_LAYOUT     1    // 0 = even rows left->right, 1 = even rows right->left
+/*
+    ADAFRUIT_NEOPXL8 UPDATE:
+
+    Aside from changes to convert from OctoWS2811 to Adafruit_NeoPXL8, the
+    big drastic change here is to eliminate many compile-time constants and
+    instead place these in a JSON configuration file on a board's CIRCUITPY
+    flash filesystem (though this is Arduino code, we can still make use of
+    that drive), and declare the LEDs at run time. Other than those
+    alterations, the code is minimally changed. Paul did the real work. :)
+
+    Run-time configuration is stored in CIRCUITPY/neopxl8.cfg and resembles:
+
+    {
+      "pins" : [ 16, 17, 18, 19, 20, 21, 22, 23 ],
+      "order" : "GRB",
+      "sync_pin" : -1,
+      "led_width" : 30,
+      "led_height" : 16,
+      "led_layout" : 0,
+      "video_xoffset" : 0,
+      "video_yoffset" : 0,
+      "video_width" : 100,
+      "video_height" : 100
+    }
+
+    If this file is missing, or if any individual elements are unspecified,
+    defaults will be used (these are noted later in the code). It's possible,
+    likely even, that there will be additional elements in this file...
+    for example, some NeoPXL8 code might use a single "length" value rather
+    than width/height, as not all projects are using a grid. Be warned that
+    JSON is highly picky and even a single missing or excess comma will stop
+    everything, so read through it very carefully if encountering an error.
+*/
+
+// In original code, these were constants LED_WIDTH, LED_HEIGHT and
+// LED_LAYOUT. Values here are defaults but can override in config file.
+// led_height MUST be a multiple of 8. When 16, 24, 32 are used, each strip
+// spans 2, 3, 4 rows. led_layout indicates how strips are arranged.
+uint16_t led_width  = 30; // Number of LEDs horizontally
+uint16_t led_height = 16; // Number of LEDs vertically
+uint8_t  led_layout = 0;  // 0 = even rows left->right, 1 = right->left
 
 // The portion of the video image to show on this set of LEDs.  All 4 numbers
 // are percentages, from 0 to 100.  For a large LED installation with many
-// Teensy 3.0 boards driving groups of LEDs, these parameters allow you to
-// program each Teensy to tell the video application which portion of the
-// video it displays.  By reading these numbers, the video application can
-// automatically configure itself, regardless of which serial port COM number
-// or device names are assigned to each Teensy 3.0 by your operating system.
-#define VIDEO_XOFFSET  0
-#define VIDEO_YOFFSET  0       // display entire image
-#define VIDEO_WIDTH    100
-#define VIDEO_HEIGHT   100
+// boards driving groups of LEDs, these parameters allow you to program each
+// one to tell the video application which portion of the video it displays.
+// By reading these numbers, the video application can automatically configure
+// itself, regardless of which serial port COM number or device names are
+// assigned to each board by your operating system. 0/0/100/100 displays the
+// entire image on one board's LEDs. With two boards, this could be split
+// between them, 0/0/100/50 for the top and 0/50/100/50 for the bottom.
+// As with the led_* values, defaults do NOT need to be specified here,
+// that's done in setup().
+uint8_t video_xoffset =   0;
+uint8_t video_yoffset =   0;
+uint8_t video_width   = 100;
+uint8_t video_height  = 100;
 
-//#define VIDEO_XOFFSET  0
-//#define VIDEO_YOFFSET  0     // display upper half
-//#define VIDEO_WIDTH    100
-//#define VIDEO_HEIGHT   50
-
-//#define VIDEO_XOFFSET  0
-//#define VIDEO_YOFFSET  50    // display lower half
-//#define VIDEO_WIDTH    100
-//#define VIDEO_HEIGHT   50
-
-
-const int ledsPerStrip = LED_WIDTH * LED_HEIGHT / 8;
-uint8_t imageBuffer[LED_WIDTH * LED_HEIGHT * 3];
+uint8_t *imageBuffer;     // Serial LED data is received here
+uint32_t imageBufferSize; // Size (in bytes) of imageBuffer
+int8_t   sync_pin = -1;   // If multiple boards, wire pins together
 uint32_t lastFrameSyncTime = 0;
 
-Adafruit_NeoPXL8 leds(ledsPerStrip, pins, COLOR_ORDER);
+Adafruit_NeoPXL8 *leds; // NeoPXL8 object is allocated after reading config
+
+void error_handler(const char *message, uint16_t speed) {
+  Serial.print("Error: ");
+  Serial.println(message);
+  if (speed) { // Fatal error, blink LED
+    pinMode(LED_BUILTIN, OUTPUT);
+    for (;;) {
+      digitalWrite(LED_BUILTIN, (millis() / speed) & 1);
+      yield(); // Keep filesystem accessible for editing
+    }
+  } else { // Not fatal, just show message
+    Serial.println("Continuing with defaults");
+  }
+}
 
 void setup() {
-  pinMode(SYNC_PIN, INPUT_PULLUP); // Frame Sync
+  // CHANGE these to match your strandtest findings (or use .cfg file):
+  int8_t pins[8] = NEOPXL8_DEFAULT_PINS;
+  uint16_t order = NEO_GRB;
+
+  // Start the CIRCUITPY flash filesystem first. Very important!
+  FatVolume *fs = Adafruit_CPFS::begin();
+
+  // Start Serial AFTER FFS begin, else CIRCUITPY won't show on computer.
+  Serial.begin(115200);
+  //while(!Serial);
+  delay(1000);
   Serial.setTimeout(50);
-  if (!leds.begin()) {
-    pinMode(LED_BUILTIN, OUTPUT);
-    for (;;) digitalWrite(LED_BUILTIN, (millis() / 500) & 1);
+
+  if (fs == NULL) {
+    error_handler("Can't access CIRCUITPY drive", 0);
+  } else {
+    FatFile file;
+    StaticJsonDocument<1024> doc;
+    DeserializationError error;
+
+    // Open NeoPXL8 configuration file and attempt to decode JSON data within.
+    if ((file = fs->open("neopxl8.cfg", FILE_READ))) {
+      error = deserializeJson(doc, file);
+      file.close();
+    } else {
+      error_handler("neopxl8.cfg not found", 0);
     }
-  leds.show();
+
+    if(error) {
+      error_handler("neopxl8.cfg syntax error", 0);
+      Serial.print("JSON error: ");
+      Serial.println(error.c_str());
+    } else {
+      // Config is valid, override defaults in program variables...
+
+      JsonVariant v = doc["pins"];
+      if (v.is<JsonArray>()) {
+        uint8_t n = v.size() < 8 ? v.size() : 8;
+        for (uint8_t i = 0; i < n; i++)
+          pins[i] = v[i].as<int>();
+      }
+
+      v = doc["order"];
+      if (v.is<const char *>()) order = Adafruit_NeoPixel::str2order(v);
+
+      sync_pin      = doc["sync_pin"]      | sync_pin;
+      led_width     = doc["led_width"]     | led_width;
+      led_height    = doc["led_height"]    | led_height;
+      led_layout    = doc["led_layout"]    | led_layout;
+      video_xoffset = doc["video_xoffset"] | video_xoffset;
+      video_yoffset = doc["video_yoffset"] | video_yoffset;
+      video_width   = doc["video_width"]   | video_width;
+      video_height  = doc["video_height"]  | video_height;
+    } // end JSON OK
+  } // end filesystem OK
+
+  // Any errors after this point are unrecoverable and program will stop.
+
+  // Dynamically allocate NeoPXL8 object
+  leds = new Adafruit_NeoPXL8(led_width * led_height / 8, pins, order);
+  if (leds == NULL) error_handler("NeoPXL8 allocation", 100);
+
+  // Allocate imageBuffer
+  imageBufferSize = led_width * led_height * 3;
+  imageBuffer = (uint8_t *)malloc(imageBufferSize);
+  if (imageBuffer == NULL) error_handler("Image buffer allocation", 200);
+
+  if (!leds->begin()) error_handler("NeoPXL8 begin() failed", 500);
+
+  // At this point, everything is fully configured, allocated and started!
+
+  leds->show(); // LEDs off ASAP
+
+  if (sync_pin >= 0) pinMode(sync_pin, INPUT_PULLUP);
 }
 
 void loop() {
@@ -166,17 +274,17 @@ void loop() {
     unsigned int usecUntilFrameSync = 0;
     int count = Serial.readBytes((char *)&usecUntilFrameSync, 2);
     if (count != 2) return;
-    count = Serial.readBytes((char *)imageBuffer, sizeof(imageBuffer));
-    if (count == sizeof(imageBuffer)) {
+    count = Serial.readBytes((char *)imageBuffer, imageBufferSize);
+    if (count == imageBufferSize) {
       unsigned int endAt = micros();
       unsigned int usToWaitBeforeSyncOutput = 100;
       if (endAt - startAt < usecUntilFrameSync) {
         usToWaitBeforeSyncOutput = usecUntilFrameSync - (endAt - startAt);
       }
-      digitalWrite(SYNC_PIN, HIGH);
-      pinMode(SYNC_PIN, OUTPUT);
+      digitalWrite(sync_pin, HIGH);
+      pinMode(sync_pin, OUTPUT);
       delayMicroseconds(usToWaitBeforeSyncOutput);
-      digitalWrite(SYNC_PIN, LOW);
+      digitalWrite(sync_pin, LOW);
       // WS2811 update begins immediately after falling edge of frame sync
       convert_and_show();
     }
@@ -188,32 +296,32 @@ void loop() {
     unsigned int usecUntilFrameSync = 0;
     int count = Serial.readBytes((char *)&usecUntilFrameSync, 2);
     if (count != 2) return;
-    count = Serial.readBytes((char *)imageBuffer, sizeof(imageBuffer));
-    if (count == sizeof(imageBuffer)) {
-      digitalWrite(SYNC_PIN, HIGH);
-      pinMode(SYNC_PIN, OUTPUT);
+    count = Serial.readBytes((char *)imageBuffer, imageBufferSize);
+    if (count == imageBufferSize) {
+      digitalWrite(sync_pin, HIGH);
+      pinMode(sync_pin, OUTPUT);
       uint32_t now, elapsed;
       do {
         now = micros();
         elapsed = now - lastFrameSyncTime;
       } while (elapsed < usecUntilFrameSync); // wait
       lastFrameSyncTime = now;
-      digitalWrite(SYNC_PIN, LOW);
+      digitalWrite(sync_pin, LOW);
       // WS2811 update begins immediately after falling edge of frame sync
       convert_and_show();
     }
 
   } else if (startChar == '%') {
     // receive a "slave" frame - wait to show it until the frame sync arrives
-    pinMode(SYNC_PIN, INPUT_PULLUP);
+    pinMode(sync_pin, INPUT_PULLUP);
     unsigned int unusedField = 0;
     int count = Serial.readBytes((char *)&unusedField, 2);
     if (count != 2) return;
-    count = Serial.readBytes((char *)imageBuffer, sizeof(imageBuffer));
-    if (count == sizeof(imageBuffer)) {
+    count = Serial.readBytes((char *)imageBuffer, imageBufferSize);
+    if (count == imageBufferSize) {
       uint32_t startTime = millis();
-      while (digitalRead(SYNC_PIN) != HIGH && (millis() - startTime) < 30) ; // wait for sync high
-      while (digitalRead(SYNC_PIN) != LOW && (millis() - startTime) < 30) ;  // wait for sync high->low
+      while (digitalRead(sync_pin) != HIGH && (millis() - startTime) < 30) ; // wait for sync high
+      while (digitalRead(sync_pin) != LOW && (millis() - startTime) < 30) ;  // wait for sync high->low
       // WS2811 update begins immediately after falling edge of frame sync
       if ((millis() - startTime) < 30) {
         convert_and_show();
@@ -226,23 +334,23 @@ void loop() {
   } else if (startChar == '?') {
     // when the video application asks, give it all our info
     // for easy and automatic configuration
-    Serial.print(LED_WIDTH);
+    Serial.print(led_width);
     Serial.write(',');
-    Serial.print(LED_HEIGHT);
+    Serial.print(led_height);
     Serial.write(',');
-    Serial.print(LED_LAYOUT);
+    Serial.print(led_layout);
     Serial.write(',');
     Serial.print(0);
     Serial.write(',');
     Serial.print(0);
     Serial.write(',');
-    Serial.print(VIDEO_XOFFSET);
+    Serial.print(video_xoffset);
     Serial.write(',');
-    Serial.print(VIDEO_YOFFSET);
+    Serial.print(video_yoffset);
     Serial.write(',');
-    Serial.print(VIDEO_WIDTH);
+    Serial.print(video_width);
     Serial.write(',');
-    Serial.print(VIDEO_HEIGHT);
+    Serial.print(video_height);
     Serial.write(',');
     Serial.print(0);
     Serial.write(',');
@@ -258,25 +366,27 @@ void loop() {
 
 void convert_and_show() {
   uint8_t *ptr = imageBuffer;
-  for (int y=0; y<LED_HEIGHT; y++) {
-    for (int x=0; x<LED_WIDTH; x++) {
-      int pixelIndex;
-#if (LED_LAYOUT == 0)
-      // Always left-to-right
-      pixelIndex = y * LED_WIDTH + x;
-#else
-      // Even rows are left-to-right, odd are right-to-left
-      if (y & 1) {
-        pixelIndex = (y + 1) * LED_WIDTH - 1 - x;
+  if (led_layout == 0) {
+    for (int y=0; y<led_height; y++) {
+      for (int x=0; x<led_width; x++) {
+        int pixelIndex = y * led_width + x; // Always left-to-right
+        uint8_t r = leds->gamma8(*ptr++);
+        uint8_t g = leds->gamma8(*ptr++);
+        uint8_t b = leds->gamma8(*ptr++);
+        leds->setPixelColor(pixelIndex, r, g, b);
+      }
+    }
   } else {
-        pixelIndex = y * LED_WIDTH + x;
-      }
-#endif
-      uint8_t r = leds.gamma8(*ptr++);
-      uint8_t g = leds.gamma8(*ptr++);
-      uint8_t b = leds.gamma8(*ptr++);
-      leds.setPixelColor(pixelIndex, r, g, b);
+    for (int y=0; y<led_height; y++) {
+      for (int x=0; x<led_width; x++) {
+        // Even rows are left-to-right, odd are right-to-left
+        int pixelIndex = (y & 1) ? (y + 1) * led_width - 1 - x : y * led_width + x;
+        uint8_t r = leds->gamma8(*ptr++);
+        uint8_t g = leds->gamma8(*ptr++);
+        uint8_t b = leds->gamma8(*ptr++);
+        leds->setPixelColor(pixelIndex, r, g, b);
       }
     }
-  leds.show();
+  }
+  leds->show();
 }

examples/NeoPXL8HDR/VideoMSC/VideoMSC.ino

@@ -1,3 +1,6 @@
+// This sketch is Just Too Much for SAMD21 (M0) and SAMD51 (M4) boards.
+// Recommend RP2040/SCORPIO or ESP32-S3.
+
 // FIRST TIME HERE? START WITH THE NEOPXL8 (not HDR) strandtest EXAMPLE!
 // That code explains and helps troubshoot wiring and NeoPixel color format.
 // Then move on to NeoPXL8HDR strandtest, THEN try this one.
@@ -5,27 +8,27 @@
 // This is a companion to "move2msc" in the extras/Processing folder.
 // It plays preconverted videos from the on-board flash filesystem.
 
+#include "SdFat_Adafruit_Fork.h"
 #include <Adafruit_NeoPXL8.h>
+#include <Adafruit_CPFS.h> // For accessing CIRCUITPY drive
+#define ARDUINOJSON_ENABLE_COMMENTS 1
+#include <ArduinoJson.h>
 
-// CHANGE these to match your strandtest findings or this WILL NOT WORK:
-
-int8_t pins[8] = { 6, 7, 9, 8, 13, 12, 11, 10 };
-#define COLOR_ORDER NEO_GRB
-
-#define SYNC_PIN -1 // -1 = not used
-
-// This example is minimally adapted from one in PJRC's OctoWS2811 Library:
+// This example is adapted from one in PJRC's OctoWS2811 Library. Original
+// comments appear first, and Adafruit_NeoPXL8 changes follow that. Any
+// original comments about "SD card" now apply to a board's CIRCUITPY flash
+// filesystem instead.
 
 /*  OctoWS2811 VideoSDcard.ino - Video on LEDs, played from SD Card
     http://www.pjrc.com/teensy/td_libs_OctoWS2811.html
     Copyright (c) 2014 Paul Stoffregen, PJRC.COM, LLC
 
-    Permission is hereby granted, free of charge, to any person obtaining a copy
-    of this software and associated documentation files (the "Software"), to deal
-    in the Software without restriction, including without limitation the rights
-    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-    copies of the Software, and to permit persons to whom the Software is
-    furnished to do so, subject to the following conditions:
+    Permission is hereby granted, free of charge, to any person obtaining a
+    copy of this software and associated documentation files (the "Software"),
+    to deal in the Software without restriction, including without limitation
+    the rights to use, copy, modify, merge, publish, distribute, sublicense,
+    and/or sell copies of the Software, and to permit persons to whom the
+    Software is furnished to do so, subject to the following conditions:
 
     The above copyright notice and this permission notice shall be included in
     all copies or substantial portions of the Software.
@@ -34,9 +37,9 @@ int8_t pins[8] = { 6, 7, 9, 8, 13, 12, 11, 10 };
     IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
     AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-    THE SOFTWARE.
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+    DEALINGS IN THE SOFTWARE.
 
 Update: The programs to prepare the SD card video file have moved to "extras"
 https://github.com/PaulStoffregen/OctoWS2811/tree/master/extras
@@ -70,45 +73,66 @@ https://github.com/PaulStoffregen/OctoWS2811/tree/master/extras
     pin 13: SD Card, SCLK
 */
 
-#include "SPI.h"
-#include "SdFat.h"
-#include "Adafruit_SPIFlash.h"
-#include "Adafruit_TinyUSB.h"
+/*
+    ADAFRUIT_NEOPXL8 UPDATE:
 
-#define LED_WIDTH    30   // number of LEDs horizontally
-#define LED_HEIGHT   16   // number of LEDs vertically (must be multiple of 8)
-#define LED_LAYOUT   1    // 0 = even rows left->right, 1 = even rows right->left
+    Aside from changes to convert from OctoWS2811 to Adafruit_NeoPXL8, the
+    big drastic change here is to eliminate many compile-time constants and
+    instead place these in a JSON configuration file on a board's CIRCUITPY
+    flash filesystem (though this is Arduino code, we can still make use of
+    that drive), and declare the LEDs at run time. Other than those
+    alterations, the code is minimally changed. Paul did the real work. :)
+
+    Run-time configuration is stored in CIRCUITPY/neopxl8.cfg and resembles:
+
+    {
+      "pins" : [ 16, 17, 18, 19, 20, 21, 22, 23 ],
+      "order" : "GRB",
+      "led_width" : 30,
+      "led_height" : 16,
+      "led_layout" : 0
+    }
+
+    If this file is missing, or if any individual elements are unspecified,
+    defaults will be used (these are noted later in the code). It's possible,
+    likely even, that there will be additional elements in this file...
+    for example, some NeoPXL8 code might use a single "length" value rather
+    than width/height, as not all projects are using a grid. Be warned that
+    JSON is highly picky and even a single missing or excess comma will stop
+    everything, so read through it very carefully if encountering an error.
+*/
 
 #define FILENAME "mymovie.bin"
 
-const int ledsPerStrip = LED_WIDTH * LED_HEIGHT / 8;
-uint8_t imageBuffer[LED_WIDTH * LED_HEIGHT * 3];
-uint32_t timeOfLastFrame = 0;
-bool playing = false;
+// In original code, these were constants LED_WIDTH, LED_HEIGHT and
+// LED_LAYOUT. Values here are defaults but can override in config file.
+// led_height MUST be a multiple of 8. When 16, 24, 32 are used, each strip
+// spans 2, 3, 4 rows. led_layout indicates how strips are arranged.
+uint16_t led_width  = 30; // Number of LEDs horizontally
+uint16_t led_height = 16; // Number of LEDs vertically
+uint8_t  led_layout = 0;  // 0 = even rows left->right, 1 = right->left
 
-Adafruit_NeoPXL8HDR leds(ledsPerStrip, pins, COLOR_ORDER);
-
-// From tinyUSB msc_external_flash example
-#if defined(ARDUINO_ARCH_RP2040)
-  Adafruit_FlashTransport_RP2040 flashTransport;
-#elif defined(CONFIG_IDF_TARGET_ESP32S3)
-  Adafruit_FlashTransport_ESP32 flashTransport;
-#else
-  #if defined(EXTERNAL_FLASH_USE_QSPI)
-    Adafruit_FlashTransport_QSPI flashTransport;
-  #elif defined(EXTERNAL_FLASH_USE_SPI)
-    Adafruit_FlashTransport_SPI flashTransport(EXTERNAL_FLASH_USE_CS, EXTERNAL_FLASH_USE_SPI);
-  #else
-    #error No QSPI/SPI flash are defined on your board variant.h !
-  #endif
-#endif
-
-Adafruit_SPIFlash flash(&flashTransport);
-
-FatFileSystem fatfs; // file system object from SdFat
 FatFile file;
-Adafruit_USBD_MSC usb_msc; // USB Mass Storage object
-bool fs_changed = true; // Set to true when PC write to flash
+bool playing = false;
+uint32_t timeOfLastFrame = 0;
+uint8_t *imageBuffer;     // LED data from filesystem is staged here
+uint32_t imageBufferSize; // Size (in bytes) of imageBuffer
+
+Adafruit_NeoPXL8HDR *leds = NULL;
+
+void error_handler(const char *message, uint16_t speed) {
+  Serial.print("Error: ");
+  Serial.println(message);
+  if (speed) { // Fatal error, blink LED
+    pinMode(LED_BUILTIN, OUTPUT);
+    for (;;) {
+      digitalWrite(LED_BUILTIN, (millis() / speed) & 1);
+      yield(); // Keep filesystem accessible for editing
+    }
+  } else { // Not fatal, just show message
+    Serial.println("Continuing with defaults");
+  }
+}
 
 #if defined(ARDUINO_ARCH_RP2040)
 
@@ -117,14 +141,14 @@ bool fs_changed = true; // Set to true when PC write to flash
 // free for animation logic in the regular loop() function.
 
 void loop1() {
-  leds.refresh();
+  if (leds) leds->refresh();
 }
 
 // Pause just a moment before starting the refresh() loop.
 // Mass storage has a lot to do on startup and the sketch locks up
 // without this. So far it's only needed on the MSC+HDR example.
 void setup1() {
-  delay(100);
+  delay(1000);
 }
 
 #elif defined(CONFIG_IDF_TARGET_ESP32S3)
@@ -136,7 +160,7 @@ void setup1() {
 void loop0(void *param) {
   for(;;) {
     yield();
-    leds.refresh();
+    if (leds) leds->refresh();
   }
 }
 
@@ -155,33 +179,87 @@ void TC3_Handler() {
 }
 
 void timerCallback(void) {
-  leds.refresh();
+  if (leds) leds->refresh();
 }
 
 #endif // end SAMD
 
 void setup() {
-  // Flash setup from tinyUSB msc_external_flash example
-  flash.begin();
-  // Set disk vendor id, product id and revision with string up to 8, 16, 4 characters respectively
-  usb_msc.setID("Adafruit", "External Flash", "1.0");
-  usb_msc.setReadWriteCallback(msc_read_cb, msc_write_cb, msc_flush_cb); // Set callback
-  // Set disk size, block size should be 512 regardless of spi flash page size
-  usb_msc.setCapacity(flash.size()/512, 512);
-  usb_msc.setUnitReady(true); // MSC is ready for read/write
-  usb_msc.begin();
-  fatfs.begin(&flash); // Init file system on the flash
+  // CHANGE these to match your strandtest findings (or use .cfg file):
+  int8_t pins[8] = NEOPXL8_DEFAULT_PINS;
+  uint16_t order = NEO_GRB;
 
+  // Start the CIRCUITPY flash filesystem first. Very important!
+  FatVolume *fs = Adafruit_CPFS::begin();
+
+  // Start Serial AFTER FFS begin, else CIRCUITPY won't show on computer.
   Serial.begin(115200);
   //while(!Serial);
+  delay(1000);
+  Serial.setTimeout(50);
   Serial.println("VideoMSC");
 
-  if (!leds.begin()) {
-    pinMode(LED_BUILTIN, OUTPUT);
-    for (;;) digitalWrite(LED_BUILTIN, (millis() / 500) & 1);
+  if (fs == NULL) {
+    error_handler("Can't access CIRCUITPY drive", 0);
+  } else {
+    StaticJsonDocument<1024> doc;
+    DeserializationError error;
+
+    // Open NeoPXL8 configuration file and attempt to decode JSON data within.
+    if ((file = fs->open("neopxl8.cfg", FILE_READ))) {
+      error = deserializeJson(doc, file);
+      file.close();
+    } else {
+      error_handler("neopxl8.cfg not found", 0);
     }
-  leds.setBrightness(65535, 2.6); // Full brightness, 2.6 gamma factor
-  leds.show();
+
+    if(error) {
+      error_handler("neopxl8.cfg syntax error", 0);
+      Serial.print("JSON error: ");
+      Serial.println(error.c_str());
+    } else {
+      // Config is valid, override defaults in program variables...
+
+      JsonVariant v = doc["pins"];
+      if (v.is<JsonArray>()) {
+        uint8_t n = v.size() < 8 ? v.size() : 8;
+        for (uint8_t i = 0; i < n; i++)
+          pins[i] = v[i].as<int>();
+      }
+
+      v = doc["order"];
+      if (v.is<const char *>()) order = Adafruit_NeoPixel::str2order(v);
+
+      led_width  = doc["led_width"]  | led_width;
+      led_height = doc["led_height"] | led_height;
+      led_layout = doc["led_layout"] | led_layout;
+    } // end JSON OK
+  } // end filesystem OK
+
+  // Any errors after this point are unrecoverable and program will stop.
+
+    // Dynamically allocate NeoPXL8 object
+  leds = new Adafruit_NeoPXL8HDR(led_width * led_height / 8, pins, order);
+  if (leds == NULL) error_handler("NeoPXL8 allocation", 100);
+
+  // Allocate imageBuffer
+  imageBufferSize = led_width * led_height * 3;
+  imageBuffer = (uint8_t *)malloc(imageBufferSize);
+  if (imageBuffer == NULL) error_handler("Image buffer allocation", 200);
+
+  if (!leds->begin()) error_handler("NeoPXL8 begin() failed", 500);
+
+  // At this point, everything but input file is ready to go!
+
+  leds->setBrightness(65535, 2.6); // Full brightness, 2.6 gamma factor
+  leds->show(); // LEDs off ASAP
+
+  bool status = file.open(FILENAME, O_RDONLY);
+  if (!status) error_handler("Can't open movie .bin file", 1000);
+  Serial.println("File opened");
+  delay(500); // Give MSC a moment to compose itself
+  playing = true;
+  timeOfLastFrame = 0;
 
 #if defined(CONFIG_IDF_TARGET_ESP32S3)
 
@@ -205,12 +283,6 @@ void setup() {
   zerotimer.enable(true);
 
 #endif // end SAMD
-
-  bool status = file.open(FILENAME, O_RDONLY);
-  if (!status) stopWithErrorMessage("Could not read " FILENAME);
-  Serial.println("File opened");
-  playing = true;
-  timeOfLastFrame = 0;
 }
 
 // REMAINDER OF CODE IS NEARLY IDENTICAL TO NON-HDR VERSION. This version
@@ -273,8 +345,8 @@ void loop()
         unsigned int usec = header[3] | (header[4] << 8);
         unsigned int readsize = size;
 	      //Serial.printf("v: %u %u\n", size, usec);
-        if (readsize > sizeof(imageBuffer)) {
-          readsize = sizeof(imageBuffer);
+        if (readsize > imageBufferSize) {
+          readsize = imageBufferSize;
         }
         if (sd_card_read(imageBuffer, readsize)) {
           uint32_t now;
@@ -345,53 +417,29 @@ void error(const char *str)
   playing = false;
 }
 
-// when an error happens during setup, give up and print a message
-// to the serial monitor.
-void stopWithErrorMessage(const char *str)
-{
-  while (1) {
-    Serial.println(str);
-    delay(1000);
-  }
-}
-
 void convert_and_show() {
   uint8_t *ptr = imageBuffer;
-  for (int y=0; y<LED_HEIGHT; y++) {
-    for (int x=0; x<LED_WIDTH; x++) {
-      int pixelIndex;
-#if (LED_LAYOUT == 0)
-      // Always left-to-right
-      pixelIndex = y * LED_WIDTH + x;
-#else
-      // Even rows are left-to-right, odd are right-to-left
-      if (y & 1) {
-        pixelIndex = (y + 1) * LED_WIDTH - 1 - x;
-      } else {
-        pixelIndex = y * LED_WIDTH + x;
-      }
-#endif
+  if (led_layout == 0) {
+    for (int y=0; y<led_height; y++) {
+      for (int x=0; x<led_width; x++) {
+        int pixelIndex = y * led_width + x; // Always left-to-right
         uint8_t r = *ptr++;
         uint8_t g = *ptr++;
         uint8_t b = *ptr++;
-      leds.setPixelColor(pixelIndex, r, g, b);
+        leds->setPixelColor(pixelIndex, r, g, b);
       }
     }
-  leds.show();
+  } else {
+    for (int y=0; y<led_height; y++) {
+      for (int x=0; x<led_width; x++) {
+        // Even rows are left-to-right, odd are right-to-left
+        int pixelIndex = (y & 1) ? (y + 1) * led_width - 1 - x : y * led_width + x;
+        uint8_t r = *ptr++;
+        uint8_t g = *ptr++;
+        uint8_t b = *ptr++;
+        leds->setPixelColor(pixelIndex, r, g, b);
       }
-
-// More code from tinyUSB msc_external_flash example; commented there
-
-int32_t msc_read_cb (uint32_t lba, void* buffer, uint32_t bufsize) {
-  return flash.readBlocks(lba, (uint8_t*) buffer, bufsize/512) ? bufsize : -1;
     }
-
-int32_t msc_write_cb (uint32_t lba, uint8_t* buffer, uint32_t bufsize) {
-  return flash.writeBlocks(lba, buffer, bufsize/512) ? bufsize : -1;
   }
-
-void msc_flush_cb (void) {
-  flash.syncBlocks();
-  fatfs.cacheClear();
-  fs_changed = true;
+  leds->show();
 }

examples/NeoPXL8HDR/VideoSerial/VideoSerial.ino

@@ -1,30 +1,31 @@
+// This sketch is Just Too Much for SAMD21 (M0) and SAMD51 (M4) boards.
+// Recommend RP2040/SCORPIO or ESP32-S3.
+
 // FIRST TIME HERE? START WITH THE NEOPXL8 (not HDR) strandtest EXAMPLE!
 // That code explains and helps troubshoot wiring and NeoPixel color format.
 // Then move on to NeoPXL8HDR strandtest, THEN try this one.
 
 // This is a companion to "move2serial" in the extras/Processing folder.
 
+#include "SdFat_Adafruit_Fork.h"
 #include <Adafruit_NeoPXL8.h>
+#include <Adafruit_CPFS.h> // For accessing CIRCUITPY drive
+#define ARDUINOJSON_ENABLE_COMMENTS 1
+#include <ArduinoJson.h>
 
-// CHANGE these to match your strandtest findings or this WILL NOT WORK:
-
-int8_t pins[8] = { 6, 7, 9, 8, 13, 12, 11, 10 };
-#define COLOR_ORDER NEO_GRB
-
-#define SYNC_PIN -1 // -1 = not used
-
-// This example is minimally adapted from one in PJRC's OctoWS2811 Library:
+// This example is adapted from one in PJRC's OctoWS2811 Library. Original
+// comments appear first, followed by Adafruit_NeoPXL8 changes.
 
 /*  OctoWS2811 VideoDisplay.ino - Video on LEDs, from a PC, Mac, Raspberry Pi
     http://www.pjrc.com/teensy/td_libs_OctoWS2811.html
     Copyright (c) 2013 Paul Stoffregen, PJRC.COM, LLC
 
-    Permission is hereby granted, free of charge, to any person obtaining a copy
-    of this software and associated documentation files (the "Software"), to deal
-    in the Software without restriction, including without limitation the rights
-    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-    copies of the Software, and to permit persons to whom the Software is
-    furnished to do so, subject to the following conditions:
+    Permission is hereby granted, free of charge, to any person obtaining a
+    copy of this software and associated documentation files (the "Software"),
+    to deal in the Software without restriction, including without limitation
+    the rights to use, copy, modify, merge, publish, distribute, sublicense,
+    and/or sell copies of the Software, and to permit persons to whom the
+    Software is furnished to do so, subject to the following conditions:
 
     The above copyright notice and this permission notice shall be included in
     all copies or substantial portions of the Software.
@@ -33,9 +34,9 @@ int8_t pins[8] = { 6, 7, 9, 8, 13, 12, 11, 10 };
     IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
     AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-    THE SOFTWARE.
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+    DEALINGS IN THE SOFTWARE.
 
 Update: The movie2serial program which transmit data has moved to "extras"
 https://github.com/PaulStoffregen/OctoWS2811/tree/master/extras
@@ -75,44 +76,68 @@ https://github.com/PaulStoffregen/OctoWS2811/tree/master/extras
     ports on the same motherboard, may give poor performance.
 */
 
-// The actual arrangement of the LEDs connected to this Teensy 3.0 board.
-// LED_HEIGHT *must* be a multiple of 8.  When 16, 24, 32 are used, each
-// strip spans 2, 3, 4 rows.  LED_LAYOUT indicates the direction the strips
-// are arranged.  If 0, each strip begins on the left for its first row,
-// then goes right to left for its second row, then left to right,
-// zig-zagging for each successive row.
-#define LED_WIDTH      30   // number of LEDs horizontally
-#define LED_HEIGHT     16   // number of LEDs vertically (must be multiple of 8)
-#define LED_LAYOUT     1    // 0 = even rows left->right, 1 = even rows right->left
+/*
+    ADAFRUIT_NEOPXL8 UPDATE:
+
+    Aside from changes to convert from OctoWS2811 to Adafruit_NeoPXL8, the
+    big drastic change here is to eliminate many compile-time constants and
+    instead place these in a JSON configuration file on a board's CIRCUITPY
+    flash filesystem (though this is Arduino code, we can still make use of
+    that drive), and declare the LEDs at run time. Other than those
+    alterations, the code is minimally changed. Paul did the real work. :)
+
+    Run-time configuration is stored in CIRCUITPY/neopxl8.cfg and resembles:
+
+    {
+      "pins" : [ 16, 17, 18, 19, 20, 21, 22, 23 ],
+      "order" : "GRB",
+      "sync_pin" : -1,
+      "led_width" : 30,
+      "led_height" : 16,
+      "led_layout" : 0,
+      "video_xoffset" : 0,
+      "video_yoffset" : 0,
+      "video_width" : 100,
+      "video_height" : 100
+    }
+
+    If this file is missing, or if any individual elements are unspecified,
+    defaults will be used (these are noted later in the code). It's possible,
+    likely even, that there will be additional elements in this file...
+    for example, some NeoPXL8 code might use a single "length" value rather
+    than width/height, as not all projects are using a grid. Be warned that
+    JSON is highly picky and even a single missing or excess comma will stop
+    everything, so read through it very carefully if encountering an error.
+*/
+
+// In original code, these were constants LED_WIDTH, LED_HEIGHT and
+// LED_LAYOUT. Values here are defaults but can override in config file.
+// led_height MUST be a multiple of 8. When 16, 24, 32 are used, each strip
+// spans 2, 3, 4 rows. led_layout indicates how strips are arranged.
+uint16_t led_width  = 30; // Number of LEDs horizontally
+uint16_t led_height = 16; // Number of LEDs vertically
+uint8_t  led_layout = 0;  // 0 = even rows left->right, 1 = right->left
 
 // The portion of the video image to show on this set of LEDs.  All 4 numbers
 // are percentages, from 0 to 100.  For a large LED installation with many
-// Teensy 3.0 boards driving groups of LEDs, these parameters allow you to
-// program each Teensy to tell the video application which portion of the
-// video it displays.  By reading these numbers, the video application can
-// automatically configure itself, regardless of which serial port COM number
-// or device names are assigned to each Teensy 3.0 by your operating system.
-#define VIDEO_XOFFSET  0
-#define VIDEO_YOFFSET  0       // display entire image
-#define VIDEO_WIDTH    100
-#define VIDEO_HEIGHT   100
+// boards driving groups of LEDs, these parameters allow you to program each
+// one to tell the video application which portion of the video it displays.
+// By reading these numbers, the video application can automatically configure
+// itself, regardless of which serial port COM number or device names are
+// assigned to each board by your operating system. 0/0/100/100 displays the
+// entire image on one board's LEDs. With two boards, this could be split
+// between them, 0/0/100/50 for the top and 0/50/100/50 for the bottom.
+uint8_t video_xoffset =   0;
+uint8_t video_yoffset =   0;
+uint8_t video_width   = 100;
+uint8_t video_height  = 100;
 
-//#define VIDEO_XOFFSET  0
-//#define VIDEO_YOFFSET  0     // display upper half
-//#define VIDEO_WIDTH    100
-//#define VIDEO_HEIGHT   50
-
-//#define VIDEO_XOFFSET  0
-//#define VIDEO_YOFFSET  50    // display lower half
-//#define VIDEO_WIDTH    100
-//#define VIDEO_HEIGHT   50
-
-
-const int ledsPerStrip = LED_WIDTH * LED_HEIGHT / 8;
-uint8_t imageBuffer[LED_WIDTH * LED_HEIGHT * 3];
+uint8_t *imageBuffer;     // Serial LED data is received here
+uint32_t imageBufferSize; // Size (in bytes) of imageBuffer
+int8_t   sync_pin = -1;   // If multiple boards, wire pins together
 uint32_t lastFrameSyncTime = 0;
 
-Adafruit_NeoPXL8HDR leds(ledsPerStrip, pins, COLOR_ORDER);
+Adafruit_NeoPXL8HDR *leds = NULL; // NeoPXL8HDR object is allocated after reading config
 
 #if defined(ARDUINO_ARCH_RP2040)
 
@@ -121,7 +146,7 @@ Adafruit_NeoPXL8HDR leds(ledsPerStrip, pins, COLOR_ORDER);
 // free for animation logic in the regular loop() function.
 
 void loop1() {
-  leds.refresh();
+  if (leds) leds->refresh();
 }
 
 #elif defined(CONFIG_IDF_TARGET_ESP32S3)
@@ -133,7 +158,7 @@ void loop1() {
 void loop0(void *param) {
   for(;;) {
     yield();
-    leds.refresh();
+    if (leds) leds->refresh();
   }
 }
 
@@ -152,20 +177,101 @@ void TC3_Handler() {
 }
 
 void timerCallback(void) {
-  leds.refresh();
+  if (leds) leds->refresh();
 }
 
 #endif // end SAMD
 
-void setup() {
-  pinMode(SYNC_PIN, INPUT_PULLUP); // Frame Sync
-  Serial.setTimeout(50);
-  if (!leds.begin()) {
+void error_handler(const char *message, uint16_t speed) {
+  Serial.print("Error: ");
+  Serial.println(message);
+  if (speed) { // Fatal error, blink LED
     pinMode(LED_BUILTIN, OUTPUT);
-    for (;;) digitalWrite(LED_BUILTIN, (millis() / 500) & 1);
+    for (;;) {
+      digitalWrite(LED_BUILTIN, (millis() / speed) & 1);
+      yield(); // Keep filesystem accessible for editing
     }
-  leds.setBrightness(65535, 2.6); // Full brightness, 2.6 gamma factor
-  leds.show();
+  } else { // Not fatal, just show message
+    Serial.println("Continuing with defaults");
+  }
+}
+
+void setup() {
+  // CHANGE these to match your strandtest findings (or use .cfg file):
+  int8_t pins[8] = NEOPXL8_DEFAULT_PINS;
+  uint16_t order = NEO_GRB;
+
+  // Start the CIRCUITPY flash filesystem first. Very important!
+  FatVolume *fs = Adafruit_CPFS::begin();
+
+  // Start Serial AFTER FFS begin, else CIRCUITPY won't show on computer.
+  Serial.begin(115200);
+  //while(!Serial);
+  delay(1000);
+  Serial.setTimeout(50);
+
+  if (fs == NULL) {
+    error_handler("Can't access CIRCUITPY drive", 0);
+  } else {
+    FatFile file;
+    StaticJsonDocument<1024> doc;
+    DeserializationError error;
+
+    // Open NeoPXL8 configuration file and attempt to decode JSON data within.
+    if ((file = fs->open("neopxl8.cfg", FILE_READ))) {
+      error = deserializeJson(doc, file);
+      file.close();
+    } else {
+      error_handler("neopxl8.cfg not found", 0);
+    }
+
+    if(error) {
+      error_handler("neopxl8.cfg syntax error", 0);
+      Serial.print("JSON error: ");
+      Serial.println(error.c_str());
+    } else {
+      // Config is valid, override defaults in program variables...
+
+      JsonVariant v = doc["pins"];
+      if (v.is<JsonArray>()) {
+        uint8_t n = v.size() < 8 ? v.size() : 8;
+        for (uint8_t i = 0; i < n; i++)
+          pins[i] = v[i].as<int>();
+      }
+
+      v = doc["order"];
+      if (v.is<const char *>()) order = Adafruit_NeoPixel::str2order(v);
+
+      sync_pin      = doc["sync_pin"]      | sync_pin;
+      led_width     = doc["led_width"]     | led_width;
+      led_height    = doc["led_height"]    | led_height;
+      led_layout    = doc["led_layout"]    | led_layout;
+      video_xoffset = doc["video_xoffset"] | video_xoffset;
+      video_yoffset = doc["video_yoffset"] | video_yoffset;
+      video_width   = doc["video_width"]   | video_width;
+      video_height  = doc["video_height"]  | video_height;
+    } // end JSON OK
+  } // end filesystem OK
+
+  // Any errors after this point are unrecoverable and program will stop.
+
+  // Dynamically allocate NeoPXL8HDR object
+  leds = new Adafruit_NeoPXL8HDR(led_width * led_height / 8, pins, order);
+  if (leds == NULL) error_handler("NeoPXL8HDR allocation", 100);
+
+  // Allocate imageBuffer
+  imageBufferSize = led_width * led_height * 3;
+  imageBuffer = (uint8_t *)malloc(imageBufferSize);
+  if (imageBuffer == NULL) error_handler("Image buffer allocation", 200);
+
+  if (!leds->begin()) error_handler("NeoPXL8HDR begin() failed", 500);
+
+  // At this point, everything is fully configured, allocated and started!
+
+  leds->setBrightness(65535, 2.6); // Full brightness, 2.6 gamma factor
+  leds->show(); // LEDs off ASAP
+
+  if (sync_pin >= 0) pinMode(sync_pin, INPUT_PULLUP);
 
 #if defined(CONFIG_IDF_TARGET_ESP32S3)
 
@@ -237,17 +343,17 @@ void loop() {
     unsigned int usecUntilFrameSync = 0;
     int count = Serial.readBytes((char *)&usecUntilFrameSync, 2);
     if (count != 2) return;
-    count = Serial.readBytes((char *)imageBuffer, sizeof(imageBuffer));
-    if (count == sizeof(imageBuffer)) {
+    count = Serial.readBytes((char *)imageBuffer, imageBufferSize);
+    if (count == imageBufferSize) {
       unsigned int endAt = micros();
       unsigned int usToWaitBeforeSyncOutput = 100;
       if (endAt - startAt < usecUntilFrameSync) {
         usToWaitBeforeSyncOutput = usecUntilFrameSync - (endAt - startAt);
       }
-      digitalWrite(SYNC_PIN, HIGH);
-      pinMode(SYNC_PIN, OUTPUT);
+      digitalWrite(sync_pin, HIGH);
+      pinMode(sync_pin, OUTPUT);
       delayMicroseconds(usToWaitBeforeSyncOutput);
-      digitalWrite(SYNC_PIN, LOW);
+      digitalWrite(sync_pin, LOW);
       // WS2811 update begins immediately after falling edge of frame sync
       convert_and_show();
     }
@@ -259,32 +365,32 @@ void loop() {
     unsigned int usecUntilFrameSync = 0;
     int count = Serial.readBytes((char *)&usecUntilFrameSync, 2);
     if (count != 2) return;
-    count = Serial.readBytes((char *)imageBuffer, sizeof(imageBuffer));
-    if (count == sizeof(imageBuffer)) {
-      digitalWrite(SYNC_PIN, HIGH);
-      pinMode(SYNC_PIN, OUTPUT);
+    count = Serial.readBytes((char *)imageBuffer, imageBufferSize);
+    if (count == imageBufferSize) {
+      digitalWrite(sync_pin, HIGH);
+      pinMode(sync_pin, OUTPUT);
       uint32_t now, elapsed;
       do {
         now = micros();
         elapsed = now - lastFrameSyncTime;
       } while (elapsed < usecUntilFrameSync); // wait
       lastFrameSyncTime = now;
-      digitalWrite(SYNC_PIN, LOW);
+      digitalWrite(sync_pin, LOW);
       // WS2811 update begins immediately after falling edge of frame sync
       convert_and_show();
     }
 
   } else if (startChar == '%') {
     // receive a "slave" frame - wait to show it until the frame sync arrives
-    pinMode(SYNC_PIN, INPUT_PULLUP);
+    pinMode(sync_pin, INPUT_PULLUP);
     unsigned int unusedField = 0;
     int count = Serial.readBytes((char *)&unusedField, 2);
     if (count != 2) return;
-    count = Serial.readBytes((char *)imageBuffer, sizeof(imageBuffer));
-    if (count == sizeof(imageBuffer)) {
+    count = Serial.readBytes((char *)imageBuffer, imageBufferSize);
+    if (count == imageBufferSize) {
       uint32_t startTime = millis();
-      while (digitalRead(SYNC_PIN) != HIGH && (millis() - startTime) < 30) ; // wait for sync high
-      while (digitalRead(SYNC_PIN) != LOW && (millis() - startTime) < 30) ;  // wait for sync high->low
+      while (digitalRead(sync_pin) != HIGH && (millis() - startTime) < 30) ; // wait for sync high
+      while (digitalRead(sync_pin) != LOW && (millis() - startTime) < 30) ;  // wait for sync high->low
       // WS2811 update begins immediately after falling edge of frame sync
       if ((millis() - startTime) < 30) {
         convert_and_show();
@@ -297,23 +403,23 @@ void loop() {
   } else if (startChar == '?') {
     // when the video application asks, give it all our info
     // for easy and automatic configuration
-    Serial.print(LED_WIDTH);
+    Serial.print(led_width);
     Serial.write(',');
-    Serial.print(LED_HEIGHT);
+    Serial.print(led_height);
     Serial.write(',');
-    Serial.print(LED_LAYOUT);
+    Serial.print(led_layout);
     Serial.write(',');
     Serial.print(0);
     Serial.write(',');
     Serial.print(0);
     Serial.write(',');
-    Serial.print(VIDEO_XOFFSET);
+    Serial.print(video_xoffset);
     Serial.write(',');
-    Serial.print(VIDEO_YOFFSET);
+    Serial.print(video_yoffset);
     Serial.write(',');
-    Serial.print(VIDEO_WIDTH);
+    Serial.print(video_width);
     Serial.write(',');
-    Serial.print(VIDEO_HEIGHT);
+    Serial.print(video_height);
     Serial.write(',');
     Serial.print(0);
     Serial.write(',');
@@ -329,25 +435,27 @@ void loop() {
 
 void convert_and_show() {
   uint8_t *ptr = imageBuffer;
-  for (int y=0; y<LED_HEIGHT; y++) {
-    for (int x=0; x<LED_WIDTH; x++) {
-      int pixelIndex;
-#if (LED_LAYOUT == 0)
-      // Always left-to-right
-      pixelIndex = y * LED_WIDTH + x;
-#else
-      // Even rows are left-to-right, odd are right-to-left
-      if (y & 1) {
-        pixelIndex = (y + 1) * LED_WIDTH - 1 - x;
-      } else {
-        pixelIndex = y * LED_WIDTH + x;
-      }
-#endif
+  if (led_layout == 0) {
+    for (int y=0; y<led_height; y++) {
+      for (int x=0; x<led_width; x++) {
+        int pixelIndex = y * led_width + x; // Always left-to-right
         uint8_t r = *ptr++;
         uint8_t g = *ptr++;
         uint8_t b = *ptr++;
-      leds.setPixelColor(pixelIndex, r, g, b);
+        leds->setPixelColor(pixelIndex, r, g, b);
       }
     }
-  leds.show();
+  } else {
+    for (int y=0; y<led_height; y++) {
+      for (int x=0; x<led_width; x++) {
+        // Even rows are left-to-right, odd are right-to-left
+        int pixelIndex = (y & 1) ? (y + 1) * led_width - 1 - x : y * led_width + x;
+        uint8_t r = *ptr++;
+        uint8_t g = *ptr++;
+        uint8_t b = *ptr++;
+        leds->setPixelColor(pixelIndex, r, g, b);
+      }
+    }
+  }
+  leds->show();
 }

library.properties

@@ -1,5 +1,5 @@
 name=Adafruit NeoPXL8
-version=1.2.0
+version=1.4.0
 author=Adafruit
 maintainer=Adafruit <info@adafruit.com>
 sentence=Arduino library for controlling 8 NeoPixel LED strips using DMA on ATSAMD21, ATSAMD51, RP2040 and ESP32S3
@@ -7,4 +7,4 @@ paragraph=Arduino library for controlling 8 NeoPixel LED strips using DMA on ATS
 category=Display
 url=https://github.com/adafruit/Adafruit_NeoPXL8
 architectures=samd, rp2040, esp32
-depends=Adafruit NeoPixel, Adafruit Zero DMA Library, Adafruit ZeroTimer Library, SdFat - Adafruit Fork, Adafruit SPIFlash, Adafruit TinyUSB Library
+depends=Adafruit NeoPixel, Adafruit Zero DMA Library, Adafruit ZeroTimer Library, SdFat - Adafruit Fork, Adafruit SPIFlash, Adafruit TinyUSB Library, ArduinoJson, Adafruit InternalFlash, FlashStorage, Adafruit CPFS