_PM_stop: Don't HardFault when _PM_begin failed

When _PM_begin fails, it leaves the object in a partially-uninitialized
state.  To recover any allocated storage, we need to call _PM_free;
but if the allocation of core->screenData failed, then other internal
pointers such as core->oe.setReg are not set, and the actions in
_PM_stop will cause a HardFault.

This is a partial fix for adafruit/circuitpython#3184.

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,46 @@
+Thank you for opening an issue on an Adafruit Arduino library repository.  To
+improve the speed of resolution please review the following guidelines and
+common troubleshooting steps below before creating the issue:
+
+- **Do not use GitHub issues for troubleshooting projects and issues.**  Instead use
+  the forums at http://forums.adafruit.com to ask questions and troubleshoot why
+  something isn't working as expected.  In many cases the problem is a common issue
+  that you will more quickly receive help from the forum community.  GitHub issues
+  are meant for known defects in the code.  If you don't know if there is a defect
+  in the code then start with troubleshooting on the forum first.
+
+- **If following a tutorial or guide be sure you didn't miss a step.** Carefully
+  check all of the steps and commands to run have been followed.  Consult the
+  forum if you're unsure or have questions about steps in a guide/tutorial.
+
+- **For Arduino projects check these very common issues to ensure they don't apply**:
+
+  - For uploading sketches or communicating with the board make sure you're using
+    a **USB data cable** and **not** a **USB charge-only cable**.  It is sometimes
+    very hard to tell the difference between a data and charge cable!  Try using the
+    cable with other devices or swapping to another cable to confirm it is not
+    the problem.
+
+  - **Be sure you are supplying adequate power to the board.**  Check the specs of
+    your board and plug in an external power supply.  In many cases just
+    plugging a board into your computer is not enough to power it and other
+    peripherals.
+
+  - **Double check all soldering joints and connections.**  Flakey connections
+    cause many mysterious problems.  See the [guide to excellent soldering](https://learn.adafruit.com/adafruit-guide-excellent-soldering/tools) for examples of good solder joints.
+
+  - **Ensure you are using an official Arduino or Adafruit board.** We can't
+    guarantee a clone board will have the same functionality and work as expected
+    with this code and don't support them.
+
+If you're sure this issue is a defect in the code and checked the steps above
+please fill in the following fields to provide enough troubleshooting information.
+You may delete the guideline and text above to just leave the following details:
+
+- Arduino board:  **INSERT ARDUINO BOARD NAME/TYPE HERE**
+
+- Arduino IDE version (found in Arduino -> About Arduino menu):  **INSERT ARDUINO
+  VERSION HERE**
+
+- List the steps to reproduce the problem below (if possible attach a sketch or
+  copy the sketch code in too): **LIST REPRO STEPS BELOW**

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,26 @@
+Thank you for creating a pull request to contribute to Adafruit's GitHub code!
+Before you open the request please review the following guidelines and tips to
+help it be more easily integrated:
+
+- **Describe the scope of your change--i.e. what the change does and what parts
+  of the code were modified.**  This will help us understand any risks of integrating
+  the code.
+
+- **Describe any known limitations with your change.**  For example if the change
+  doesn't apply to a supported platform of the library please mention it.
+
+- **Please run any tests or examples that can exercise your modified code.**  We
+  strive to not break users of the code and running tests/examples helps with this
+  process.
+
+Thank you again for contributing!  We will try to test and integrate the change
+as soon as we can, but be aware we have many GitHub repositories to manage and
+can't immediately respond to every request.  There is no need to bump or check in
+on a pull request (it will clutter the discussion of the request).
+
+Also don't be worried if the request is closed or not integrated--sometimes the
+priorities of Adafruit's GitHub code (education, ease of use) might not match the
+priorities of the pull request.  Don't fret, the open source community thrives on
+forks and GitHub makes it easy to keep your changes in a forked repo.
+
+After reviewing the guidelines above you can delete this text from the pull request.

.github/workflows/githubci.yml

@@ -0,0 +1,37 @@
+name: Arduino Library CI
+
+on: [pull_request, push, repository_dispatch]
+
+jobs:
+  build:
+    strategy:
+      fail-fast: false
+      matrix:
+        arduino-platform: ["metro_m0", "metro_m4", "nrf52840", "esp32"]
+
+    runs-on: ubuntu-latest
+    
+    steps:
+    - uses: actions/setup-python@v1
+      with:
+        python-version: '3.x'
+    - uses: actions/checkout@v2
+    - uses: actions/checkout@v2
+      with:
+         repository: adafruit/ci-arduino
+         path: ci
+
+    - name: pre-install
+      run: bash ci/actions_install.sh
+
+    - name: test platforms
+      run: python3 ci/build_platform.py ${{ matrix.arduino-platform }}
+
+    - name: clang
+      run: python3 ci/run-clang-format.py -e "ci/*" -e "bin/*" -r . 
+
+    - name: doxygen
+      env:
+        GH_REPO_TOKEN: ${{ secrets.GH_REPO_TOKEN }}
+        PRETTYNAME : "Adafruit Protomatter"
+      run: bash ci/doxy_gen_and_deploy.sh

.gitignore

@@ -0,0 +1,4 @@
+# Our handy .gitignore for automation ease
+Doxyfile*
+doxygen_sqlite3.db
+html

Adafruit_Protomatter.cpp

@@ -1,3 +1,38 @@
+/*!
+ * @file Adafruit_Protomatter.cpp
+ *
+ * @mainpage Adafruit Protomatter RGB LED matrix library.
+ *
+ * @section intro_sec Introduction
+ *
+ * This is documentation for Adafruit's protomatter library for HUB75-style
+ * RGB LED matrices. It is designed to work with various matrices sold by
+ * Adafruit ("HUB75" is a vague term and other similar matrices are not
+ * guaranteed to work). This file is the Arduino-specific calls; the
+ * underlying C code is more platform-neutral.
+ *
+ * Adafruit invests time and resources providing this open source code,
+ * please support Adafruit and open-source hardware by purchasing products
+ * from Adafruit!
+ *
+ * @section dependencies Dependencies
+ *
+ * This library depends on
+ * <a href="https://github.com/adafruit/Adafruit-GFX-Library">Adafruit_GFX</a>
+ * being present on your system. Please make sure you have installed the
+ * latest version before using this library.
+ *
+ * @section author Author
+ *
+ * Written by Phil "Paint Your Dragon" Burgess and Jeff Epler for
+ * Adafruit Industries, with contributions from the open source community.
+ *
+ * @section license License
+ *
+ * BSD license, all text here must be included in any redistribution.
+ *
+ */
+
 // Arduino-specific wrapper for the Protomatter C library (provides
 // constructor and so forth, builds on Adafruit_GFX). There should
 // not be any device-specific #ifdefs here. See notes in core.c and
@@ -5,7 +40,7 @@
 
 #include "Adafruit_Protomatter.h" // Also includes core.h & Adafruit_GFX.h
 
-extern Protomatter_core *_PM_protoPtr; // In core.c (via arch.h)
+extern Protomatter_core *_PM_protoPtr; ///< In core.c (via arch.h)
 
 // Overall matrix refresh rate (frames/second) is a function of matrix width
 // and chain length, number of address lines, number of bit planes, CPU speed
@@ -21,67 +56,50 @@ extern Protomatter_core *_PM_protoPtr; // In core.c (via arch.h)
 // refresh slower than this, and in many cases will...just need to set an
 // upper limit to avoid excessive CPU load). An incredibly long comment block
 // for a single constant, thank you for coming to my TED talk!
-#define _PM_MAX_REFRESH_HZ 250
+#define _PM_MAX_REFRESH_HZ 250 ///< Upper limit (ish) to matrix refresh rate
 
 // Time (in milliseconds) to pause following any change in address lines
 // (individually or collectively). Some matrices respond slowly there...
 // must pause on change for matrix to catch up. Defined here (rather than
 // arch.h) because it's not architecture-specific.
-#define _PM_ROW_DELAY 8
+#define _PM_ROW_DELAY 8 ///< Delay time between row address line changes (ms)
 
+Adafruit_Protomatter::Adafruit_Protomatter(uint16_t bitWidth, uint8_t bitDepth,
+                                           uint8_t rgbCount, uint8_t *rgbList,
+                                           uint8_t addrCount, uint8_t *addrList,
+                                           uint8_t clockPin, uint8_t latchPin,
+                                           uint8_t oePin, bool doubleBuffer,
+                                           void *timer)
+    : GFXcanvas16(bitWidth,
+                  (2 << min((int)addrCount, 5)) * min((int)rgbCount, 5)) {
+  if (bitDepth > 6)
+    bitDepth = 6; // GFXcanvas16 color limit (565)
 
-Adafruit_Protomatter::Adafruit_Protomatter(
-  uint16_t bitWidth, uint8_t bitDepth,
-  uint8_t rgbCount, uint8_t *rgbList,
-  uint8_t addrCount, uint8_t *addrList,
-  uint8_t clockPin, uint8_t latchPin, uint8_t oePin,
-  bool doubleBuffer, void *timer) :
-  GFXcanvas16(bitWidth, (2 << min(addrCount, 5)) * min(rgbCount, 5)) {
-    if(bitDepth > 6)  bitDepth = 6;   // GFXcanvas16 color limit (565)
-
-    // Arguments are passed through to the C _PM_init() function which does
-    // some input validation and minor allocation. Return value is ignored
-    // because we can't really do anything about it in a C++ constructor.
-    // The class begin() function checks rgbPins for NULL to determine
-    // whether to proceed or indicate an error.
-    (void)_PM_init(&core, bitWidth, bitDepth, rgbCount, rgbList,
-      addrCount, addrList, clockPin, latchPin, oePin, doubleBuffer, timer);
+  // Arguments are passed through to the C _PM_init() function which does
+  // some input validation and minor allocation. Return value is ignored
+  // because we can't really do anything about it in a C++ constructor.
+  // The class begin() function checks rgbPins for NULL to determine
+  // whether to proceed or indicate an error.
+  (void)_PM_init(&core, bitWidth, bitDepth, rgbCount, rgbList, addrCount,
+                 addrList, clockPin, latchPin, oePin, doubleBuffer, timer);
 }
 
 Adafruit_Protomatter::~Adafruit_Protomatter(void) {
-    _PM_free(&core);
-    _PM_protoPtr = NULL;
+  _PM_free(&core);
+  _PM_protoPtr = NULL;
 }
 
 ProtomatterStatus Adafruit_Protomatter::begin(void) {
-    _PM_protoPtr = &core;
-    _PM_begin(&core);
-    return PROTOMATTER_OK;
+  _PM_protoPtr = &core;
+  return _PM_begin(&core);
 }
 
 // Transfer data from GFXcanvas16 to the matrix framebuffer's weird
 // internal format. The actual conversion functions referenced below
 // are in core.c, reasoning is explained there.
 void Adafruit_Protomatter::show(void) {
-
-    // Destination address is computed in convert function
-    // (based on active buffer value, if double-buffering),
-    // just need to pass in the canvas buffer address and
-    // width in pixels.
-    if(core.bytesPerElement == 1) {
-        _PM_convert_565_byte(&core, getBuffer(), WIDTH);
-    } else if(core.bytesPerElement == 2) {
-        _PM_convert_565_word(&core, getBuffer(), WIDTH);
-    } else {
-        _PM_convert_565_long(&core, getBuffer(), WIDTH);
-    }
-
-    if(core.doubleBuffer) {
-        core.swapBuffers = 1;
-        // To avoid overwriting data on the matrix, don't return
-        // until the timer ISR has performed the swap at the right time.
-        while(core.swapBuffers);
-    }
+  _PM_convert_565(&core, getBuffer(), WIDTH);
+  _PM_swapbuffer_maybe(&core);
 }
 
 // Returns current value of frame counter and resets its value to zero.
@@ -89,5 +107,5 @@ void Adafruit_Protomatter::show(void) {
 // intervals), can be used to get a rough frames-per-second value for
 // the matrix (since this is difficult to estimate beforehand).
 uint32_t Adafruit_Protomatter::getFrameCount(void) {
-    return _PM_getFrameCount(_PM_protoPtr);
+  return _PM_getFrameCount(_PM_protoPtr);
 }

Adafruit_Protomatter.h

@@ -7,22 +7,99 @@
 #include "core.h"
 #include <Adafruit_GFX.h>
 
+/*!
+    @brief  Class representing the Arduino-facing side of the Protomatter
+            library. Subclass of Adafruit_GFX's GFXcanvas16 to allow all
+            the drawing operations.
+*/
 class Adafruit_Protomatter : public GFXcanvas16 {
-  public:
-    Adafruit_Protomatter(uint16_t bitWidth, uint8_t bitDepth,
-      uint8_t rgbCount, uint8_t *rgbList,
-      uint8_t addrCount, uint8_t *addrList,
-      uint8_t clockPin, uint8_t latchPin, uint8_t oePin,
-      bool doubleBuffer, void *timer=NULL);
-    ~Adafruit_Protomatter(void);
-    ProtomatterStatus begin(void);
-    void              show(void);
-    uint32_t          getFrameCount(void);
-  private:
-    Protomatter_core  core;                         // Underlying C struct
-    void              convert_byte(uint8_t  *dest); // GFXcanvas16-to-matrix
-    void              convert_word(uint16_t *dest); // conversion functions
-    void              convert_long(uint32_t *dest); // for 8/16/32 bit bufs
+public:
+  /*!
+    @brief  Adafruit_Protomatter constructor.
+    @param  bitWidth      Total width of RGB matrix chain, in pixels.
+                          Usu. some multiple of 32, but maybe exceptions.
+    @param  bitDepth      Color "depth" in bitplanes, determines range of
+                          shades of red, green and blue. e.g. passing 4
+                          bits = 16 shades ea. R,G,B = 16x16x16 = 4096
+                          colors. Max is 6, since the GFX library works
+                          with "565" RGB colors (6 bits green, 5 red/blue).
+    @param  rgbCount      Number of "sets" of RGB data pins, each set
+                          containing 6 pins (2 ea. R,G,B). Typically 1,
+                          indicating a single matrix (or matrix chain).
+                          In theory (but not yet extensively tested),
+                          multiple sets of pins can be driven in parallel,
+                          up to 5 on some devices (if the hardware design
+                          provides all those bits on one PORT).
+    @param  rgbList       A uint8_t array of pins (Arduino pin numbering),
+                          6X the prior rgbCount value, corresponding to
+                          the 6 output color bits for a matrix (or chain).
+                          Order is upper-half red, green, blue, lower-half
+                          red, green blue (repeat for each add'l chain).
+                          All the RGB pins (plus the clock pin below on
+                          some architectures) MUST be on the same PORT
+                          register. It's recommended (but not required)
+                          that all RGB pins (and clock depending on arch)
+                          be within the same byte of a PORT (but do not
+                          need to be sequential or contiguous within that
+                          byte) for more efficient RAM utilization. For
+                          two concurrent chains, same principle but 16-bit
+                          word instead of byte.
+    @param  addrCount     Number of row address lines required of matrix.
+                          Total pixel height is then 2 x 2^addrCount, e.g.
+                          32-pixel-tall matrices have 4 row address lines.
+    @param  addrList      A uint8_t array of pins (Arduino pin numbering),
+                          one per row address line.
+    @param  clockPin      RGB clock pin (Arduino pin #).
+    @param  latchPin      RGB data latch pin (Arduino pin #).
+    @param  oePin         Output enable pin (Arduino pin #), active low.
+    @param  doubleBuffer  If true, two matrix buffers are allocated,
+                          so changing display contents doesn't introduce
+                          artifacts mid-conversion. Requires ~2X RAM.
+    @param  timer         Pointer to timer peripheral or timer-related
+                          struct (architecture-dependent), or NULL to
+                          use a default timer ID (also arch-dependent).
+  */
+  Adafruit_Protomatter(uint16_t bitWidth, uint8_t bitDepth, uint8_t rgbCount,
+                       uint8_t *rgbList, uint8_t addrCount, uint8_t *addrList,
+                       uint8_t clockPin, uint8_t latchPin, uint8_t oePin,
+                       bool doubleBuffer, void *timer = NULL);
+  ~Adafruit_Protomatter(void);
+
+  /*!
+    @brief  Start a Protomatter matrix display running -- initialize
+            pins, timer and interrupt into existence.
+    @return A ProtomatterStatus status, one of:
+            PROTOMATTER_OK if everything is good.
+            PROTOMATTER_ERR_PINS if data and/or clock pins are split
+            across different PORTs.
+            PROTOMATTER_ERR_MALLOC if insufficient RAM to allocate
+            display memory.
+            PROTOMATTER_ERR_ARG if a bad value was passed to the
+            constructor.
+  */
+  ProtomatterStatus begin(void);
+
+  /*!
+    @brief Process data from GFXcanvas16 to the matrix framebuffer's
+           internal format for display.
+  */
+  void show(void);
+
+  /*!
+    @brief  Returns current value of frame counter and resets its value
+            to zero. Two calls to this, timed one second apart (or use
+            math with other intervals), can be used to get a rough
+            frames-per-second value for the matrix (since this is
+            difficult to estimate beforehand).
+    @return Frame count since previous call to function, as a uint32_t.
+  */
+  uint32_t getFrameCount(void);
+
+private:
+  Protomatter_core core;             // Underlying C struct
+  void convert_byte(uint8_t *dest);  // GFXcanvas16-to-matrix
+  void convert_word(uint16_t *dest); // conversion functions
+  void convert_long(uint32_t *dest); // for 8/16/32 bit bufs
 };
 
 #endif // _ADAFRUIT_PROTOMATTER_H_

README.md

@@ -1,4 +1,4 @@
-# Adafruit_Protomatter
+# Adafruit_Protomatter [![Build Status](https://github.com/adafruit/Adafruit_Protomatter/workflows/Arduino%20Library%20CI/badge.svg)](https://github.com/adafruit/Adafruit_Protomatter/actions)
 
 "I used protomatter in the Genesis matrix." - David Marcus, Star Trek III
 
@@ -6,8 +6,6 @@ Code for driving HUB75-style RGB LED matrices, targeted at 32-bit MCUs
 using brute-force GPIO (that is, not relying on DMA or other specialized
 peripherals beyond a timer interrupt, goal being portability).
 
-Name might change as it's nondescriptive and tedious to type in code.
-
 # Matrix Concepts and Jargon
 
 HUB75 RGB LED matrices are basically a set of six concurrent shift register

core.h

@@ -1,3 +1,19 @@
+/*!
+ * @file core.h
+ *
+ * Part of Adafruit's Protomatter library for HUB75-style RGB LED matrices.
+ *
+ * Adafruit invests time and resources providing this open source code,
+ * please support Adafruit and open-source hardware by purchasing
+ * products from Adafruit!
+ *
+ * Written by Phil "Paint Your Dragon" Burgess and Jeff Epler for
+ * Adafruit Industries, with contributions from the open source community.
+ *
+ * BSD license, all text here must be included in any redistribution.
+ *
+ */
+
 #ifndef _PROTOMATTER_CORE_H_
 #define _PROTOMATTER_CORE_H_
 
@@ -5,103 +21,240 @@
 extern "C" {
 #endif
 
-#include <stdint.h>
 #include <stdbool.h>
+#include <stdint.h>
 
-// Status type returned by some functions.
+/** Status type returned by some functions. */
 typedef enum {
-    PROTOMATTER_OK,         // Everything is hunky-dory!
-    PROTOMATTER_ERR_PINS,   // Clock and/or data pins on different PORTs
-    PROTOMATTER_ERR_MALLOC, // Couldn't allocate memory for display
-    PROTOMATTER_ERR_ARG,    // Bad input to function
+  PROTOMATTER_OK,         // Everything is hunky-dory!
+  PROTOMATTER_ERR_PINS,   // Clock and/or data pins on different PORTs
+  PROTOMATTER_ERR_MALLOC, // Couldn't allocate memory for display
+  PROTOMATTER_ERR_ARG,    // Bad input to function
 } ProtomatterStatus;
 
-// Struct for matrix control lines NOT related to RGB data or clock, i.e.
-// latch, OE and address lines. RGB data and clock ("RGBC") are handled
-// differently as they have specific requirements (and might use a toggle
-// register if present). The data conversion functions need bitmasks for
-// RGB data but do NOT need the set or clear registers, so those items
-// are also declared as separate things in the core structure that follows.
+/** Struct for matrix control lines NOT related to RGB data or clock, i.e.
+    latch, OE and address lines. RGB data and clock ("RGBC") are handled
+    differently as they have specific requirements (and might use a toggle
+    register if present). The data conversion functions need bitmasks for
+    RGB data but do NOT need the set or clear registers, so those items are
+    also declared as separate things in the core structure that follows. */
 typedef struct {
-    volatile uint32_t *setReg;          // GPIO bit set register
-    volatile uint32_t *clearReg;        // GPIO bit clear register
-    uint32_t           bit;             // GPIO bitmask
-    uint8_t            pin;             // Some identifier, e.g. Arduino pin #
+  volatile void *setReg;   ///< GPIO bit set register
+  volatile void *clearReg; ///< GPIO bit clear register
+  uint32_t bit;            ///< GPIO bitmask
+  uint8_t pin;             ///< Some unique ID, e.g. Arduino pin #
 } _PM_pin;
 
-// Struct with info about an RGB matrix chain and lots of state and buffer
-// details for the library. Toggle-related items in this structure MUST be
-// declared even if the device lacks GPIO bit-toggle registers (i.e. don't
-// do an ifdef check around these). All hardware-specific details (including
-// the presence or lack of toggle registers) are isolated to a single
-// file -- arch.h -- which should ONLY be included by core.c, and ifdef'ing
-// them would result in differing representations of this structure which
-// must be shared between the library and calling code. (An alternative is
-// to put any toggle-specific stuff at the end of the struct with an ifdef
-// check, but that's just dirty pool and asking for trouble.)
+/** Struct with info about an RGB matrix chain and lots of state and buffer
+    details for the library. Toggle-related items in this structure MUST be
+    declared even if the device lacks GPIO bit-toggle registers (i.e. don't
+    do an ifdef check around these). All hardware-specific details (including
+    the presence or lack of toggle registers) are isolated to a single
+    file -- arch.h -- which should ONLY be included by core.c, and ifdef'ing
+    them would result in differing representations of this structure which
+    must be shared between the library and calling code. (An alternative is
+    to put any toggle-specific stuff at the end of the struct with an ifdef
+    check, but that's just dirty pool and asking for trouble.) */
 typedef struct {
-    void              *timer;           // Arch-specific timer/counter info
-    void              *setReg;          // RGBC bit set register (cast to use)
-    void              *clearReg;        // RGBC bit clear register "
-    void              *toggleReg;       // RGBC bit toggle register "
-    uint8_t           *rgbPins;         // Array of RGB data pins (mult of 6)
-    void              *rgbMask;         // PORT bit mask for each RGB pin
-    uint32_t           clockMask;       // PORT bit mask for RGB clock
-    uint32_t           rgbAndClockMask; // PORT bit mask for RGB data + clock
-    volatile uint32_t *addrPortToggle;  // See singleAddrPort below
-    void              *screenData;      // Per-bitplane RGB data for matrix
-    _PM_pin            latch;           // RGB data latch
-    _PM_pin            oe;              // !OE (LOW out enable)
-    _PM_pin           *addr;            // Array of address pins
-    uint32_t           bufferSize;      // Bytes per matrix buffer
-    uint32_t           bitZeroPeriod;   // Bitplane 0 timer period
-    uint32_t           minPeriod;       // Plane 0 timer period for ~250Hz
-    volatile uint32_t  frameCount;      // For estimating refresh rate
-    uint16_t           width;           // Matrix chain width in bits
-    uint8_t            bytesPerElement; // Using 8, 16 or 32 bits of PORT?
-    uint8_t            clockPin;        // RGB clock pin identifier
-    uint8_t            parallel;        // Number of concurrent matrix outs
-    uint8_t            numAddressLines; // Number of address line pins
-    uint8_t            portOffset;      // Active 8- or 16-bit pos. in PORT
-    uint8_t            numPlanes;       // Display bitplanes (1 to 6)
-    uint8_t            numRowPairs;     // Addressable row pairs
-    bool               doubleBuffer;    // 2X buffers for clean switchover
-    bool               singleAddrPort;  // If 1, all addr lines on same PORT
-    volatile uint8_t   activeBuffer;    // Index of currently-displayed buf
-    volatile uint8_t   plane;           // Current bitplane (changes in ISR)
-    volatile uint8_t   row;             // Current scanline (changes in ISR)
-    volatile uint8_t   prevRow;         // Scanline from prior ISR
-    volatile bool      swapBuffers;     // If 1, awaiting double-buf switch
+  void *timer;                   ///< Arch-specific timer/counter info
+  void *setReg;                  ///< RGBC bit set register (cast to use)
+  void *clearReg;                ///< RGBC bit clear register "
+  void *toggleReg;               ///< RGBC bit toggle register "
+  uint8_t *rgbPins;              ///< Array of RGB data pins (mult of 6)
+  void *rgbMask;                 ///< PORT bit mask for each RGB pin
+  uint32_t clockMask;            ///< PORT bit mask for RGB clock
+  uint32_t rgbAndClockMask;      ///< PORT bit mask for RGB data + clock
+  volatile void *addrPortToggle; ///< See singleAddrPort below
+  void *screenData;              ///< Per-bitplane RGB data for matrix
+  _PM_pin latch;                 ///< RGB data latch
+  _PM_pin oe;                    ///< !OE (LOW out enable)
+  _PM_pin *addr;                 ///< Array of address pins
+  uint32_t bufferSize;           ///< Bytes per matrix buffer
+  uint32_t bitZeroPeriod;        ///< Bitplane 0 timer period
+  uint32_t minPeriod;            ///< Plane 0 timer period for ~250Hz
+  volatile uint32_t frameCount;  ///< For estimating refresh rate
+  uint16_t width;                ///< Matrix chain width in bits
+  uint8_t bytesPerElement;       ///< Using 8, 16 or 32 bits of PORT?
+  uint8_t clockPin;              ///< RGB clock pin identifier
+  uint8_t parallel;              ///< Number of concurrent matrix outs
+  uint8_t numAddressLines;       ///< Number of address line pins
+  uint8_t portOffset;            ///< Active 8- or 16-bit pos. in PORT
+  uint8_t numPlanes;             ///< Display bitplanes (1 to 6)
+  uint8_t numRowPairs;           ///< Addressable row pairs
+  bool doubleBuffer;             ///< 2X buffers for clean switchover
+  bool singleAddrPort;           ///< If 1, all addr lines on same PORT
+  volatile uint8_t activeBuffer; ///< Index of currently-displayed buf
+  volatile uint8_t plane;        ///< Current bitplane (changes in ISR)
+  volatile uint8_t row;          ///< Current scanline (changes in ISR)
+  volatile uint8_t prevRow;      ///< Scanline from prior ISR
+  volatile bool swapBuffers;     ///< If 1, awaiting double-buf switch
 } Protomatter_core;
 
 // Protomatter core function prototypes. Environment-specific code (like the
 // Adafruit_Protomatter class for Arduino) calls on these underlying things,
 // and has to provide a few extras of its own (interrupt handlers and such).
 // User code shouldn't need to invoke any of them directly.
-extern ProtomatterStatus _PM_init(Protomatter_core *core,
-  uint16_t bitWidth, uint8_t bitDepth,
-  uint8_t rgbCount, uint8_t *rgbList,
-  uint8_t addrCount, uint8_t *addrList,
-  uint8_t clockPin, uint8_t latchPin, uint8_t oePin,
-  bool doubleBuffer, void *timer);
-extern ProtomatterStatus _PM_begin(Protomatter_core *core);
-extern void              _PM_stop(Protomatter_core *core);
-extern void              _PM_resume(Protomatter_core *core);
-extern void              _PM_free(Protomatter_core *core);
-extern void              _PM_row_handler(Protomatter_core *core);
-extern uint32_t          _PM_getFrameCount(Protomatter_core *core);
-extern void              _PM_timerStart(void *tptr, uint32_t period);
-extern uint32_t          _PM_timerStop(void *tptr);
-extern uint32_t          _PM_timerGetCount(void *tptr);
 
-#if defined(ARDUINO)
-extern void _PM_convert_565_byte(Protomatter_core *core,
-  uint16_t *source, uint16_t width);
-extern void _PM_convert_565_word(Protomatter_core *core,
-  uint16_t *source, uint16_t width);
-extern void _PM_convert_565_long(Protomatter_core *core,
-  uint16_t *source, uint16_t width);
-#endif // ARDUINO
+/*!
+  @brief  Initialize values in Protomatter_core structure.
+  @param  core  Pointer to Protomatter_core structure.
+  @param  bitWidth      Total width of RGB matrix chain, in pixels.
+                        Usu. some multiple of 32, but maybe exceptions.
+  @param  bitDepth      Color "depth" in bitplanes, determines range of
+                        shades of red, green and blue. e.g. passing 4
+                        bits = 16 shades ea. R,G,B = 16x16x16 = 4096
+                        colors.
+  @param  rgbCount      Number of "sets" of RGB data pins, each set
+                        containing 6 pins (2 ea. R,G,B). Typically 1,
+                        indicating a single matrix (or matrix chain).
+                        In theory (but not yet extensively tested),
+                        multiple sets of pins can be driven in parallel,
+                        up to 5 on some devices (if the hardware design
+                        provides all those bits on one PORT).
+  @param  rgbList       A uint8_t array of pins (values are platform-
+                        dependent), 6X the prior rgbCount value,
+                        corresponding to the 6 output color bits for a
+                        matrix (or chain). Order is upper-half red, green,
+                        blue, lower-half red, green blue (repeat for each
+                        add'l chain). All the RGB pins (plus the clock pin
+                        below on some architectures) MUST be on the same
+                        PORT register. It's recommended (but not required)
+                        that all RGB pins (and clock depending on arch) be
+                        within the same byte of a PORT (but do not need to
+                        be sequential or contiguous within that byte) for
+                        more efficient RAM utilization. For two concurrent
+                        chains, same principle but 16-bit word.
+  @param  addrCount     Number of row address lines required of matrix.
+                        Total pixel height is then 2 x 2^addrCount, e.g.
+                        32-pixel-tall matrices have 4 row address lines.
+  @param  addrList      A uint8_t array of pins (platform-dependent pin
+                        numbering), one per row address line.
+  @param  clockPin      RGB clock pin (platform-dependent pin #).
+  @param  latchPin      RGB data latch pin (platform-dependent pin #).
+  @param  oePin         Output enable pin (platform-dependent pin #),
+                        active low.
+  @param  doubleBuffer  If true, two matrix buffers are allocated,
+                        so changing display contents doesn't introduce
+                        artifacts mid-conversion. Requires ~2X RAM.
+  @param  timer         Pointer to timer peripheral or timer-related
+                        struct (architecture-dependent), or NULL to
+                        use a default timer ID (also arch-dependent).
+  @return A ProtomatterStatus status, one of:
+          PROTOMATTER_OK if everything is good.
+          PROTOMATTER_ERR_PINS if data and/or clock pins are split across
+          different PORTs.
+          PROTOMATTER_ERR_MALLOC if insufficient RAM to allocate display
+          memory.
+          PROTOMATTER_ERR_ARG if a bad value (core or timer pointer) was
+          passed in.
+*/
+extern ProtomatterStatus _PM_init(Protomatter_core *core, uint16_t bitWidth,
+                                  uint8_t bitDepth, uint8_t rgbCount,
+                                  uint8_t *rgbList, uint8_t addrCount,
+                                  uint8_t *addrList, uint8_t clockPin,
+                                  uint8_t latchPin, uint8_t oePin,
+                                  bool doubleBuffer, void *timer);
+
+/*!
+  @brief  Allocate display buffers and populate additional elements of a
+          Protomatter matrix.
+  @param  core  Pointer to Protomatter_core structure.
+  @return A ProtomatterStatus status, one of:
+          PROTOMATTER_OK if everything is good.
+          PROTOMATTER_ERR_PINS if data and/or clock pins are split across
+          different PORTs.
+          PROTOMATTER_ERR_MALLOC if insufficient RAM to allocate display
+          memory.
+          PROTOMATTER_ERR_ARG if a bad value.
+*/
+extern ProtomatterStatus _PM_begin(Protomatter_core *core);
+
+/*!
+  @brief  Disable (but do not deallocate) a Protomatter matrix. Disables
+          matrix by setting OE pin HIGH and writing all-zero data to
+          matrix shift registers, so it won't halt with lit LEDs.
+  @param  core  Pointer to Protomatter_core structure.
+*/
+extern void _PM_stop(Protomatter_core *core);
+
+/*!
+  @brief  Start or restart a matrix. Initialize counters, configure and
+          start timer.
+  @param  core  Pointer to Protomatter_core structure.
+*/
+extern void _PM_resume(Protomatter_core *core);
+
+/*!
+  @brief  Deallocate memory associated with Protomatter_core structure
+          (e.g. screen data, pin lists for data and rows). Does not
+          deallocate the structure itself.
+  @param  core  Pointer to Protomatter_core structure.
+*/
+extern void _PM_free(Protomatter_core *core);
+
+/*!
+  @brief  Matrix "row handler" that's called by the timer interrupt.
+          Handles row address lines and issuing data to matrix.
+  @param  core  Pointer to Protomatter_core structure.
+*/
+extern void _PM_row_handler(Protomatter_core *core);
+
+/*!
+  @brief  Returns current value of frame counter and resets its value to
+          zero. Two calls to this, timed one second apart (or use math with
+          other intervals), can be used to get a rough frames-per-second
+          value for the matrix (since this is difficult to estimate
+          beforehand).
+  @param  core  Pointer to Protomatter_core structure.
+  @return Frame count since previous call to function, as a uint32_t.
+*/
+extern uint32_t _PM_getFrameCount(Protomatter_core *core);
+
+/*!
+  @brief  Start (or restart) a timer/counter peripheral.
+  @param  tptr    Pointer to timer/counter peripheral OR a struct
+                  encapsulating information about a timer/counter
+                  periph (architecture-dependent).
+  @param  period  Timer 'top' / rollover value.
+*/
+extern void _PM_timerStart(void *tptr, uint32_t period);
+
+/*!
+  @brief  Stop timer/counter peripheral.
+  @param  tptr    Pointer to timer/counter peripheral OR a struct
+                  encapsulating information about a timer/counter
+                  periph (architecture-dependent).
+  @return Counter value when timer was stopped.
+*/
+extern uint32_t _PM_timerStop(void *tptr);
+
+/*!
+  @brief  Query a timer/counter peripheral's current count.
+  @param  tptr    Pointer to timer/counter peripheral OR a struct
+                  encapsulating information about a timer/counter
+                  periph (architecture-dependent).
+  @return Counter value.
+*/
+extern uint32_t _PM_timerGetCount(void *tptr);
+
+/*!
+  @brief  Converts image data from GFX16 canvas to the matrices weird
+          internal format.
+  @param  core    Pointer to Protomatter_core structure.
+  @param  source  Pointer to source image data (see Adafruit_GFX 16-bit
+                  canvas type for format).
+  @param  width   Width of canvas in pixels, as this may be different than
+                  the matrix pixel width due to row padding.
+*/
+extern void _PM_convert_565(Protomatter_core *core, uint16_t *source,
+                            uint16_t width);
+
+/*!
+  @brief  Pauses until the next vertical blank to avoid 'tearing' animation
+          (if display is double-buffered). If single-buffered, has no effect.
+  @param  core  Pointer to Protomatter_core structure.
+*/
+extern void _PM_swapbuffer_maybe(Protomatter_core *core);
 
 #ifdef __cplusplus
 } // extern "C"

examples/doublebuffer/doublebuffer.ino

@@ -41,6 +41,26 @@ PA05 A4    PA13       PA21 D7    PB05       PB13
 PA06       PA14       PA22 SDA   PB06       PB14
 PA07 D9    PA15 D5    PA23 SCL   PB07       PB15
 
+FEATHER nRF52840:
+P0.00      P0.08 D12       P0.24 RXD  P1.08 D5
+P0.01      P0.09           P0.25 TXD  P1.09 D13
+P0.02 A4   P0.10 D2 (NFC)  P0.26 D9   P1.10
+P0.03 A5   P0.11 SCL       P0.27 D10  P1.11
+P0.04 A0   P0.12 SDA       P0.28 A3   P1.12
+P0.05 A1   P0.13 MOSI      P0.29      P1.13
+P0.06 D11  P0.14 SCK       P0.30 A2   P1.14
+P0.07 D6   P0.15 MISO      P0.31      P1.15
+
+FEATHER ESP32:
+P0.00          P0.08          P0.16 16/RX    P0.24          P1.00 32/A7
+P0.01          P0.09          P0.17 17/TX    P0.25 25/A1    P1.01 33/A9/SS
+P0.02          P0.10          P0.18 18/MOSI  P0.26 26/A0    P1.02 34/A2 (in)
+P0.03          P0.11          P0.19 19/MISO  P0.27 27/A10   P1.03
+P0.04 4/A5     P0.12 12/A11   P0.20          P0.28          P1.04 36/A4 (in)
+P0.05 5/SCK    P0.13 13/A12   P0.21 21       P0.29          P1.05
+P0.06          P0.14 14/A6    P0.22 22/SCL   P0.30          P1.06
+P0.07          P0.15 15/A8    P0.23 23/SDA   P0.31          P1.07 39/A3 (in)
+
 RGB Matrix FeatherWing:
 R1  D6    A   A5
 G1  D5    B   A4
@@ -55,6 +75,7 @@ the code could run there (with some work to be done in the convert_*
 functions), but would be super RAM-inefficient. Should be fine on other
 M0 devices like a Metro, if wiring manually so one can pick a contiguous
 byte of PORT bits.
+RGB+clock are on different PORTs on nRF52840.
 */
 
 #if defined(__SAMD51__)
@@ -64,12 +85,41 @@ byte of PORT bits.
   uint8_t clockPin   = 13;
   uint8_t latchPin   = 0;
   uint8_t oePin      = 1;
-#else // SAMD21
+#elif defined(_SAMD21_)
   uint8_t rgbPins[]  = {6, 7, 10, 11, 12, 13};
   uint8_t addrPins[] = {0, 1, 2, 3};
   uint8_t clockPin   = SDA;
   uint8_t latchPin   = 4;
   uint8_t oePin      = 5;
+#elif defined(NRF52_SERIES)
+  // Special nRF52840 FeatherWing pinout
+  uint8_t rgbPins[]  = {6, A5, A1, A0, A4, 11};
+  uint8_t addrPins[] = {10, 5, 13, 9};
+  uint8_t clockPin   = 12;
+  uint8_t latchPin   = PIN_SERIAL1_RX;
+  uint8_t oePin      = PIN_SERIAL1_TX;
+#elif defined(ESP32)
+  // 'Safe' pins (not overlapping any peripherals):
+  // GPIO.out: 4, 12, 13, 14, 15, 21, 27, GPIO.out1: 32, 33
+  // Peripheral-overlapping pins, sorted from 'most expendible':
+  // 16, 17 (RX, TX), 25, 26 (A0, A1), 18, 5, 9 (MOSI, SCK, MISO), 22, 23 (SCL, SDA)
+  uint8_t rgbPins[]  = {4, 12, 13, 14, 15, 21};
+  uint8_t addrPins[] = {16, 17, 25, 26};
+  uint8_t clockPin   = 27; // Must be on same port as rgbPins
+  uint8_t latchPin   = 32;
+  uint8_t oePin      = 33;
+#elif defined(ARDUINO_TEENSY40)
+  uint8_t rgbPins[]  = {15, 16, 17, 20, 21, 22}; // A1-A3, A6-A8, skips SDA,SCL
+  uint8_t addrPins[] = {2, 3, 4, 5};
+  uint8_t clockPin   = 23; // A9
+  uint8_t latchPin   = 6;
+  uint8_t oePin      = 9;
+#elif defined(ARDUINO_TEENSY41)
+  uint8_t rgbPins[]  = {26, 27, 38, 20, 21, 22}; // A12-14, A6-A8 (yes that's a 38, NOT 28!)
+  uint8_t addrPins[] = {2, 3, 4, 5};
+  uint8_t clockPin   = 23; // A9
+  uint8_t latchPin   = 6;
+  uint8_t oePin      = 9;
 #endif
 
 // Last arg here enables double-buffering

examples/protomatter/protomatter.ino

@@ -41,6 +41,26 @@ PA05 A4    PA13       PA21 D7    PB05       PB13
 PA06       PA14       PA22 SDA   PB06       PB14
 PA07 D9    PA15 D5    PA23 SCL   PB07       PB15
 
+FEATHER nRF52840:
+P0.00      P0.08 D12       P0.24 RXD  P1.08 D5
+P0.01      P0.09           P0.25 TXD  P1.09 D13
+P0.02 A4   P0.10 D2 (NFC)  P0.26 D9   P1.10
+P0.03 A5   P0.11 SCL       P0.27 D10  P1.11
+P0.04 A0   P0.12 SDA       P0.28 A3   P1.12
+P0.05 A1   P0.13 MOSI      P0.29      P1.13
+P0.06 D11  P0.14 SCK       P0.30 A2   P1.14
+P0.07 D6   P0.15 MISO      P0.31      P1.15
+
+FEATHER ESP32:
+P0.00          P0.08          P0.16 16/RX    P0.24          P1.00 32/A7
+P0.01          P0.09          P0.17 17/TX    P0.25 25/A1    P1.01 33/A9/SS
+P0.02          P0.10          P0.18 18/MOSI  P0.26 26/A0    P1.02 34/A2 (in)
+P0.03          P0.11          P0.19 19/MISO  P0.27 27/A10   P1.03
+P0.04 4/A5     P0.12 12/A11   P0.20          P0.28          P1.04 36/A4 (in)
+P0.05 5/SCK    P0.13 13/A12   P0.21 21       P0.29          P1.05
+P0.06          P0.14 14/A6    P0.22 22/SCL   P0.30          P1.06
+P0.07          P0.15 15/A8    P0.23 23/SDA   P0.31          P1.07 39/A3 (in)
+
 RGB Matrix FeatherWing:
 R1  D6    A   A5
 G1  D5    B   A4
@@ -55,6 +75,7 @@ the code could run there (with some work to be done in the convert_*
 functions), but would be super RAM-inefficient. Should be fine on other
 M0 devices like a Metro, if wiring manually so one can pick a contiguous
 byte of PORT bits.
+RGB+clock are on different PORTs on nRF52840.
 */
 
 #if defined(__SAMD51__)
@@ -64,12 +85,41 @@ byte of PORT bits.
   uint8_t clockPin   = 13;
   uint8_t latchPin   = 0;
   uint8_t oePin      = 1;
-#else // SAMD21
+#elif defined(_SAMD21_)
   uint8_t rgbPins[]  = {6, 7, 10, 11, 12, 13};
   uint8_t addrPins[] = {0, 1, 2, 3};
   uint8_t clockPin   = SDA;
   uint8_t latchPin   = 4;
   uint8_t oePin      = 5;
+#elif defined(NRF52_SERIES)
+  // Special nRF52840 FeatherWing pinout
+  uint8_t rgbPins[]  = {6, A5, A1, A0, A4, 11};
+  uint8_t addrPins[] = {10, 5, 13, 9};
+  uint8_t clockPin   = 12;
+  uint8_t latchPin   = PIN_SERIAL1_RX;
+  uint8_t oePin      = PIN_SERIAL1_TX;
+#elif defined(ESP32)
+  // 'Safe' pins (not overlapping any peripherals):
+  // GPIO.out: 4, 12, 13, 14, 15, 21, 27, GPIO.out1: 32, 33
+  // Peripheral-overlapping pins, sorted from 'most expendible':
+  // 16, 17 (RX, TX), 25, 26 (A0, A1), 18, 5, 9 (MOSI, SCK, MISO), 22, 23 (SCL, SDA)
+  uint8_t rgbPins[]  = {4, 12, 13, 14, 15, 21};
+  uint8_t addrPins[] = {16, 17, 25, 26};
+  uint8_t clockPin   = 27; // Must be on same port as rgbPins
+  uint8_t latchPin   = 32;
+  uint8_t oePin      = 33;
+#elif defined(ARDUINO_TEENSY40)
+  uint8_t rgbPins[]  = {15, 16, 17, 20, 21, 22}; // A1-A3, A6-A8, skips SDA,SCL
+  uint8_t addrPins[] = {2, 3, 4, 5};
+  uint8_t clockPin   = 23; // A9
+  uint8_t latchPin   = 6;
+  uint8_t oePin      = 9;
+#elif defined(ARDUINO_TEENSY41)
+  uint8_t rgbPins[]  = {26, 27, 38, 20, 21, 22}; // A12-14, A6-A8 (yes that's a 38, NOT 28!)
+  uint8_t addrPins[] = {2, 3, 4, 5};
+  uint8_t clockPin   = 23; // A9
+  uint8_t latchPin   = 6;
+  uint8_t oePin      = 9;
 #endif
 
 Adafruit_Protomatter matrix(

library.properties

@@ -1,10 +1,10 @@
 name=Adafruit Protomatter
-version=0.0.0
+version=1.0.3
 author=Adafruit
 maintainer=Adafruit <info@adafruit.com>
 sentence=This is a library for the Adafruit RGB LED matrix.
 paragraph=RGB LED matrix.
 category=Display
 url=https://github.com/adafruit/Adafruit_protomatter
-architectures=*
+architectures=samd,nrf52,stm32,esp32
 depends=Adafruit GFX Library