Add SPI support and FIFO functionality with proper sign extension

- Add hardware and software SPI interface support via BusIO
- Implement FIFO test example with correct 23-bit sign extension fix
- Add calculateTemperature() and calculatePressure() functions for raw data
- Refactor existing read functions to use calculation functions
- Fix SPI mode to MODE3 and rename fulltest example directory

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Adafruit_SPA06_003.cpp

@@ -97,7 +97,7 @@ bool Adafruit_SPA06_003::begin(int8_t cspin, SPIClass *theSPI) {
   }
 
   spi_dev = new Adafruit_SPIDevice(cspin, SPA06_003_DEFAULT_SPIFREQ,
-                                   SPI_BITORDER_MSBFIRST, SPI_MODE0, theSPI);
+                                   SPI_BITORDER_MSBFIRST, SPI_MODE3, theSPI);
 
   if (!spi_dev->begin()) {
     return false;
@@ -126,7 +126,7 @@ bool Adafruit_SPA06_003::begin(int8_t cspin, int8_t mosipin, int8_t misopin,
 
   spi_dev = new Adafruit_SPIDevice(cspin, sckpin, misopin, mosipin,
                                    SPA06_003_DEFAULT_SPIFREQ,
-                                   SPI_BITORDER_MSBFIRST, SPI_MODE0);
+                                   SPI_BITORDER_MSBFIRST, SPI_MODE3);
 
   if (!spi_dev->begin()) {
     return false;
@@ -685,15 +685,38 @@ float Adafruit_SPA06_003::getScalingFactor(spa06_003_oversample_t oversample) {
  *  @return Temperature in degrees Celsius
  */
 float Adafruit_SPA06_003::readTemperature() {
-  // Get current temperature oversampling setting and scale factor
-  spa06_003_oversample_t oversample = getTemperatureOversampling();
-  float kT = getScalingFactor(oversample);
-
   // Read raw temperature data (24-bit 2's complement)
   uint32_t temp_raw = getTemperatureData();
 
+  // Use the calculation function
+  return calculateTemperature(temp_raw);
+}
+
+/*!
+ *  @brief  Reads compensated pressure value in hectopascals
+ *  @return Pressure in hectopascals (hPa)
+ */
+float Adafruit_SPA06_003::readPressure() {
+  // Read raw pressure and temperature data (24-bit 2's complement)
+  uint32_t pres_raw = getPressureData();
+  uint32_t temp_raw = getTemperatureData();
+
+  // Use the calculation function
+  return calculatePressure(pres_raw, temp_raw);
+}
+
+/*!
+ *  @brief  Calculates compensated temperature from raw data
+ *  @param  raw_temp Raw 24-bit temperature data
+ *  @return Temperature in degrees Celsius
+ */
+float Adafruit_SPA06_003::calculateTemperature(uint32_t raw_temp) {
+  // Get temperature oversampling setting for scaling
+  spa06_003_oversample_t oversample = getTemperatureOversampling();
+  float kT = getScalingFactor(oversample);
+
   // Convert to signed 32-bit
-  int32_t temp_raw_signed = (int32_t)temp_raw;
+  int32_t temp_raw_signed = (int32_t)raw_temp;
 
   // Calculate scaled measurement result
   float temp_raw_sc = (float)temp_raw_signed / kT;
@@ -705,21 +728,23 @@ float Adafruit_SPA06_003::readTemperature() {
 }
 
 /*!
- *  @brief  Reads compensated pressure value in hectopascals
+ *  @brief  Calculates compensated pressure from raw data
+ *  @param  raw_pres Raw 24-bit pressure data
+ *  @param  raw_temp Raw 24-bit temperature data (for compensation)
  *  @return Pressure in hectopascals (hPa)
  */
-float Adafruit_SPA06_003::readPressure() {
-  // Get scaling factors based on current oversampling settings
-  float kP = getScalingFactor(getPressureOversampling());
-  float kT = getScalingFactor(getTemperatureOversampling());
+float Adafruit_SPA06_003::calculatePressure(uint32_t raw_pres,
+                                            uint32_t raw_temp) {
+  // Get oversampling settings for scaling
+  spa06_003_oversample_t pres_oversample = getPressureOversampling();
+  spa06_003_oversample_t temp_oversample = getTemperatureOversampling();
 
-  // Read raw pressure and temperature data (24-bit 2's complement)
-  uint32_t pres_raw = getPressureData();
-  uint32_t temp_raw = getTemperatureData();
+  float kP = getScalingFactor(pres_oversample);
+  float kT = getScalingFactor(temp_oversample);
 
   // Convert to signed 32-bit
-  int32_t pres_raw_signed = (int32_t)pres_raw;
-  int32_t temp_raw_signed = (int32_t)temp_raw;
+  int32_t pres_raw_signed = (int32_t)raw_pres;
+  int32_t temp_raw_signed = (int32_t)raw_temp;
 
   // Calculate scaled measurement results
   float pres_raw_sc = (float)pres_raw_signed / kP;
@@ -733,14 +758,13 @@ float Adafruit_SPA06_003::readPressure() {
   // Calculate compensated pressure using the formula:
   // Pcomp = c00 + c10*Praw_sc + c20*Praw_sc^2 + c30*Praw_sc^3 + c40*Praw_sc^4 +
   //         Traw_sc*(c01 + c11*Praw_sc + c21*Praw_sc^2 + c31*Praw_sc^3)
-
   float pres_comp =
       (float)c00 + (float)c10 * pres_raw_sc + (float)c20 * pres_raw_sc_2 +
       (float)c30 * pres_raw_sc_3 + (float)c40 * pres_raw_sc_4 +
       temp_raw_sc * ((float)c01 + (float)c11 * pres_raw_sc +
                      (float)c21 * pres_raw_sc_2 + (float)c31 * pres_raw_sc_3);
 
-  // Convert from Pascals to hectopascals (hPa)
+  // Convert from Pa to hPa (divide by 100)
   return pres_comp / 100.0f;
 }
 

Adafruit_SPA06_003.h

@@ -212,6 +212,8 @@ class Adafruit_SPA06_003 {
   bool reset();
   float readTemperature();
   float readPressure();
+  float calculateTemperature(uint32_t raw_temp);
+  float calculatePressure(uint32_t raw_pres, uint32_t raw_temp);
 
   Adafruit_Sensor *getTemperatureSensor();
   Adafruit_Sensor *getPressureSensor();

examples/fifotest/fifotest.ino

@@ -0,0 +1,142 @@
+/*!
+ * @file fifotest.ino
+ *
+ * Demonstrates using the SPA06_003 FIFO functionality with I2C interface.
+ * This example enables the FIFO, fills it up, then reads all data at once
+ * when the FIFO becomes full.
+ *
+ * The FIFO can store up to 32 pressure and temperature measurements,
+ * allowing for burst data collection and reducing I2C traffic.
+ *
+ * Designed specifically to work with the Adafruit SPA06_003 Breakout
+ * ----> https://www.adafruit.com/products/xxxx
+ *
+ * These sensors use I2C to communicate, 2 pins are required to interface.
+ *
+ * Written by Limor 'ladyada' Fried with assistance from Claude Code
+ * for Adafruit Industries.
+ * MIT license, check license.txt for more information
+ * All text above must be included in any redistribution
+ */
+
+#include <Adafruit_SPA06_003.h>
+
+Adafruit_SPA06_003 spa;
+
+void setup() {
+  Serial.begin(115200);
+  while (!Serial)
+    delay(10);  // will pause Zero, Leonardo, etc until serial console opens
+
+  Serial.println("Adafruit SPA06_003 FIFO Test");
+
+  // Try to initialize!
+  if (!spa.begin()) {
+    Serial.println("Failed to find SPA06_003 chip");
+    while (1) {
+      delay(10);
+    }
+  }
+  Serial.println("SPA06_003 Found!");
+
+  // Configure for FIFO operation
+  Serial.println("Configuring sensor for FIFO operation...");
+
+  // Set moderate precision for faster sampling
+  spa.setPressureOversampling(SPA06_003_OVERSAMPLE_8);     // 8x oversampling
+  spa.setTemperatureOversampling(SPA06_003_OVERSAMPLE_8);  // 8x oversampling
+
+  // Set high measurement rate to fill FIFO quickly
+  spa.setPressureMeasureRate(SPA06_003_RATE_32);     // 32 Hz
+  spa.setTemperatureMeasureRate(SPA06_003_RATE_32);  // 32 Hz
+
+  // Enable FIFO and FIFO full interrupt
+  spa.enableFIFO(true);
+  spa.setInterruptSource(true, false,
+                         false);  // Enable only FIFO full interrupt
+
+  // Start continuous measurement
+  spa.setMeasurementMode(SPA06_003_MEAS_CONTINUOUS_BOTH);
+
+  Serial.println("FIFO enabled and continuous measurement started");
+  Serial.println("Waiting for FIFO to fill...");
+  Serial.println("FIFO holds up to 32 measurements");
+  Serial.println();
+}
+
+void loop() {
+  // Check if FIFO is full
+  if (spa.isFIFOFull()) {
+    Serial.println("*** FIFO IS FULL! ***");
+    Serial.println("Reading all data from FIFO...");
+
+    uint8_t count = 0;
+
+    // Read all data from FIFO until empty
+    uint32_t last_temp_raw =
+        0;  // Store last temperature for pressure compensation
+    while (!spa.isFIFOEmpty() && count < 64) {  // Safety limit
+      // Read raw 24-bit data from FIFO (always from pressure registers)
+      uint32_t raw_data = spa.getPressureData();
+
+      // Check LSB to determine measurement type
+      bool is_pressure = (raw_data & 0x01) == 1;
+
+      // Clear the LSB for actual measurement calculation and properly handle
+      // sign extension
+      uint32_t measurement_data = raw_data & 0xFFFFFE;
+
+      // After clearing LSB, we now have a 23-bit signed value
+      // Check if bit 22 is set (sign bit of the 23-bit number)
+      if (measurement_data & 0x400000) {
+        // Sign extend from 23 bits to 32 bits
+        measurement_data |= 0xFF800000;
+      }
+
+      Serial.print("Sample ");
+      Serial.print(count + 1);
+      Serial.print(": ");
+
+      if (is_pressure) {
+        // This is pressure data - need temperature for compensation
+        float pressure = spa.calculatePressure(measurement_data, last_temp_raw);
+        Serial.print("Pressure=");
+        Serial.print(pressure, 2);
+        Serial.println(" hPa");
+      } else {
+        // This is temperature data
+        last_temp_raw = measurement_data;  // Store for pressure compensation
+        float temperature = spa.calculateTemperature(measurement_data);
+        Serial.print("Temperature=");
+        Serial.print(temperature, 2);
+        Serial.println(" °C");
+      }
+
+      count++;
+      delay(10);  // Small delay between reads
+    }
+
+    Serial.print("Total samples read from FIFO: ");
+    Serial.println(count);
+    Serial.println();
+    Serial.println("FIFO emptied. Waiting for next fill...");
+    Serial.println("-----------------------------------");
+    Serial.println();
+  }
+
+  // Check FIFO status periodically
+  static unsigned long lastStatusCheck = 0;
+  if (millis() - lastStatusCheck > 1000) {  // Check every second
+    Serial.print("FIFO Status - ");
+    Serial.print("Empty: ");
+    Serial.print(spa.isFIFOEmpty() ? "Yes" : "No");
+    Serial.print(", Full: ");
+    Serial.print(spa.isFIFOFull() ? "Yes" : "No");
+    Serial.print(", Enabled: ");
+    Serial.println(spa.isFIFOEnabled() ? "Yes" : "No");
+
+    lastStatusCheck = millis();
+  }
+
+  delay(100);  // Check FIFO status every 100ms
+}

examples/fulltest/fulltest.ino

@@ -102,13 +102,15 @@ void printOversampling(spa06_003_oversample_t prc) {
 
 void setup() {
   Serial.begin(115200);
-  while (!Serial) delay(10);
+  while (!Serial)
+    delay(10);
 
   Serial.println("SPA06_003 test!");
 
   if (!spa.begin()) {
     Serial.println("Could not find a valid SPA06_003 sensor, check wiring!");
-    while (1) delay(10);
+    while (1)
+      delay(10);
   }
 
   Serial.println(F("SPA06_003 sensor found and initialized!"));
@@ -147,7 +149,8 @@ void setup() {
 
   spa.setInterruptPolarity(SPA06_003_INT_ACTIVE_HIGH);
 
-  spa.setInterruptSource(false /*fifo*/, true /*temp_ready*/, true /*pres_ready*/);
+  spa.setInterruptSource(false /*fifo*/, true /*temp_ready*/,
+                         true /*pres_ready*/);
 
   spa.setTemperatureOversampling(SPA06_003_OVERSAMPLE_8);
 

examples/sensorapi/sensorapi.ino

@@ -1,10 +1,10 @@
 /*!
  * @file sensorapi.ino
  *
- * Demonstrates using the SPA06_003 sensor with Adafruit's Unified Sensor interface.
- * This example shows how to get sensor information and read values using the
- * standardized Adafruit Sensor API, which allows easy integration with other
- * sensor libraries and data logging systems.
+ * Demonstrates using the SPA06_003 sensor with Adafruit's Unified Sensor
+ * interface. This example shows how to get sensor information and read values
+ * using the standardized Adafruit Sensor API, which allows easy integration
+ * with other sensor libraries and data logging systems.
  *
  * The begin() function automatically configures the sensor for:
  * - Highest precision (128x oversampling)
@@ -34,14 +34,17 @@ Adafruit_Sensor *spa_pressure;
 
 void setup() {
   Serial.begin(115200);
-  while (!Serial) delay(10);     // will pause Zero, Leonardo, etc until serial console opens
+  while (!Serial)
+    delay(10);  // will pause Zero, Leonardo, etc until serial console opens
 
   Serial.println("Adafruit SPA06_003 Unified Sensor API Test");
 
   // Try to initialize the sensor
   if (!spa.begin()) {
     Serial.println("Failed to find SPA06_003 chip");
-    while (1) { delay(10); }
+    while (1) {
+      delay(10);
+    }
   }
   Serial.println("SPA06_003 Found!");
 
@@ -83,23 +86,41 @@ void printSensorDetails() {
   sensor_t sensor;
   spa_temp->getSensor(&sensor);
   Serial.println("Temperature Sensor:");
-  Serial.print("  Sensor Type: "); Serial.println(sensor.name);
-  Serial.print("  Driver Ver:  "); Serial.println(sensor.version);
-  Serial.print("  Unique ID:   "); Serial.println(sensor.sensor_id);
-  Serial.print("  Max Value:   "); Serial.print(sensor.max_value); Serial.println(" °C");
-  Serial.print("  Min Value:   "); Serial.print(sensor.min_value); Serial.println(" °C");
-  Serial.print("  Resolution:  "); Serial.print(sensor.resolution); Serial.println(" °C");
+  Serial.print("  Sensor Type: ");
+  Serial.println(sensor.name);
+  Serial.print("  Driver Ver:  ");
+  Serial.println(sensor.version);
+  Serial.print("  Unique ID:   ");
+  Serial.println(sensor.sensor_id);
+  Serial.print("  Max Value:   ");
+  Serial.print(sensor.max_value);
+  Serial.println(" °C");
+  Serial.print("  Min Value:   ");
+  Serial.print(sensor.min_value);
+  Serial.println(" °C");
+  Serial.print("  Resolution:  ");
+  Serial.print(sensor.resolution);
+  Serial.println(" °C");
   Serial.println("");
 
   // Print pressure sensor details
   spa_pressure->getSensor(&sensor);
   Serial.println("Pressure Sensor:");
-  Serial.print("  Sensor Type: "); Serial.println(sensor.name);
-  Serial.print("  Driver Ver:  "); Serial.println(sensor.version);
-  Serial.print("  Unique ID:   "); Serial.println(sensor.sensor_id);
-  Serial.print("  Max Value:   "); Serial.print(sensor.max_value); Serial.println(" hPa");
-  Serial.print("  Min Value:   "); Serial.print(sensor.min_value); Serial.println(" hPa");
-  Serial.print("  Resolution:  "); Serial.print(sensor.resolution); Serial.println(" hPa");
+  Serial.print("  Sensor Type: ");
+  Serial.println(sensor.name);
+  Serial.print("  Driver Ver:  ");
+  Serial.println(sensor.version);
+  Serial.print("  Unique ID:   ");
+  Serial.println(sensor.sensor_id);
+  Serial.print("  Max Value:   ");
+  Serial.print(sensor.max_value);
+  Serial.println(" hPa");
+  Serial.print("  Min Value:   ");
+  Serial.print(sensor.min_value);
+  Serial.println(" hPa");
+  Serial.print("  Resolution:  ");
+  Serial.print(sensor.resolution);
+  Serial.println(" hPa");
   Serial.println("");
 
   Serial.println("------------------------------------");

examples/simpletest/simpletest.ino

@@ -26,14 +26,17 @@ Adafruit_SPA06_003 spa;
 
 void setup() {
   Serial.begin(115200);
-  while (!Serial) delay(10);     // will pause Zero, Leonardo, etc until serial console opens
+  while (!Serial)
+    delay(10);  // will pause Zero, Leonardo, etc until serial console opens
 
   Serial.println("Adafruit SPA06_003 Simple Test");
 
   // Try to initialize!
   if (!spa.begin()) {
     Serial.println("Failed to find SPA06_003 chip");
-    while (1) { delay(10); }
+    while (1) {
+      delay(10);
+    }
   }
   Serial.println("SPA06_003 Found!");
 }

examples/spi_test/spi_test.ino

@@ -35,7 +35,8 @@ Adafruit_SPA06_003 spa;
 
 void setup() {
   Serial.begin(115200);
-  while (!Serial) delay(10);     // will pause Zero, Leonardo, etc until serial console opens
+  while (!Serial)
+    delay(10);  // will pause Zero, Leonardo, etc until serial console opens
 
   Serial.println("Adafruit SPA06_003 SPI Test");
 
@@ -44,10 +45,20 @@ void setup() {
   if (!spa.begin(SPA_CS_PIN, &SPI)) {
     Serial.println("Failed to find SPA06_003 chip via hardware SPI");
     Serial.println("Check wiring and try software SPI example");
-    while (1) { delay(10); }
+    while (1) {
+      delay(10);
+    }
   }
   Serial.println("SPA06_003 Found via Hardware SPI!");
 
+  // Alternative: Software SPI (uncomment to use instead of hardware SPI)
+  // Default ATmega328 pins: MOSI=11, MISO=12, SCK=13, CS=10
+  // if (!spa.begin(10, 11, 12, 13)) {
+  //   Serial.println("Failed to find SPA06_003 chip via software SPI");
+  //   while (1) { delay(10); }
+  // }
+  // Serial.println("SPA06_003 Found via Software SPI!");
+
   Serial.println("Starting continuous measurement...");
   Serial.println("Temperature and pressure readings:");
   Serial.println("Format: Temp (°C) | Pressure (hPa)");