initial

Adafruit_OPT4048.cpp

@@ -0,0 +1,115 @@
+#include "Adafruit_OPT4048.h"
+
+/**
+ * @brief Construct a new Adafruit_OPT4048 object.
+ */
+Adafruit_OPT4048::Adafruit_OPT4048() {
+  i2c_dev = nullptr;
+}
+
+/**
+ * @brief Destroy the Adafruit_OPT4048 object, frees I2C device.
+ */
+Adafruit_OPT4048::~Adafruit_OPT4048() {
+  if (i2c_dev) {
+    delete i2c_dev;
+    i2c_dev = nullptr;
+  }
+}
+
+/**
+ * @brief Initialize the OPT4048 sensor over I2C.
+ *
+ * Deletes any existing I2C device instance, then creates a new one.
+ *
+ * @param addr I2C 7-bit address of the sensor (default OPT4048_DEFAULT_ADDR).
+ * @param wire Pointer to TwoWire instance (default &Wire).
+ * @return true if initialization was successful, false otherwise.
+ */
+bool Adafruit_OPT4048::begin(uint8_t addr, TwoWire *wire) {
+  // Clean up old instance if reinitializing
+  if (i2c_dev) {
+    delete i2c_dev;
+    i2c_dev = nullptr;
+  }
+  // Create I2C device
+  i2c_dev = new Adafruit_I2CDevice(addr, wire);
+  if (!i2c_dev || !i2c_dev->begin()) {
+    return false;
+  }
+  // Verify device ID to ensure correct chip is connected
+  {
+    Adafruit_BusIO_Register idreg(i2c_dev, OPT4048_REG_DEVICE_ID, 2, MSBFIRST);
+    uint16_t id = idreg.read();
+    // Default reset device ID is 0x0821
+    if (id != 0x0821) {
+      return false;
+    }
+  }
+  return true;
+}
+/**
+ * @brief Read all four channels, verify CRC, and return raw ADC code values.
+ *
+ * Reads registers for channels 0-3 in one burst, checks the CRC bits for each,
+ * and computes the 20-bit ADC code = mantissa << exponent.
+ *
+ * @param ch0 Pointer to store channel 0 ADC code.
+ * @param ch1 Pointer to store channel 1 ADC code.
+ * @param ch2 Pointer to store channel 2 ADC code.
+ * @param ch3 Pointer to store channel 3 ADC code.
+ * @return true if read succeeds and all CRC checks pass, false otherwise.
+ */
+bool Adafruit_OPT4048::getChannels(float *ch0, float *ch1, float *ch2, float *ch3) {
+  if (!i2c_dev) {
+    return false;
+  }
+  uint8_t buf[16];
+  uint8_t reg = OPT4048_REG_CH0_MSB;
+  if (!i2c_dev->write_then_read(&reg, 1, buf, sizeof(buf))) {
+    return false;
+  }
+  for (uint8_t ch = 0; ch < 4; ch++) {
+    uint16_t msb = ((uint16_t)buf[4 * ch] << 8) | buf[4 * ch + 1];
+    uint16_t lsb = ((uint16_t)buf[4 * ch + 2] << 8) | buf[4 * ch + 3];
+    uint8_t exp = (msb >> 12) & 0x0F;
+    uint32_t mant = ((msb & 0x0FFF) << 8) | ((lsb >> 8) & 0xFF);
+    uint32_t code = mant << exp;
+    uint8_t crc = lsb & 0x0F;
+    // Compute CRC bits
+    uint8_t x0 = 0;
+    for (uint8_t i = 0; i < 4; i++) {
+      x0 ^= (exp >> i) & 1;
+    }
+    for (uint8_t i = 0; i < 20; i++) {
+      x0 ^= (mant >> i) & 1;
+    }
+    for (uint8_t i = 0; i < 4; i++) {
+      x0 ^= (crc >> i) & 1;
+    }
+    uint8_t x1 = ((crc >> 1) & 1) ^ ((crc >> 3) & 1);
+    for (uint8_t i = 1; i < 20; i += 2) {
+      x1 ^= (mant >> i) & 1;
+    }
+    x1 ^= (exp >> 1) & 1;
+    x1 ^= (exp >> 3) & 1;
+    uint8_t x2 = ((crc >> 3) & 1);
+    for (uint8_t i = 3; i < 20; i += 4) {
+      x2 ^= (mant >> i) & 1;
+    }
+    x2 ^= (exp >> 3) & 1;
+    uint8_t x3 = ((mant >> 3) & 1) ^ ((mant >> 11) & 1) ^ ((mant >> 19) & 1);
+    // Verify CRC
+    if (((crc & 1) != x0) || (((crc >> 1) & 1) != x1) || (((crc >> 2) & 1) != x2) || (((crc >> 3) & 1) != x3)) {
+      return false;
+    }
+    // Assign output
+    switch (ch) {
+      case 0: *ch0 = (float)code; break;
+      case 1: *ch1 = (float)code; break;
+      case 2: *ch2 = (float)code; break;
+      case 3: *ch3 = (float)code; break;
+    }
+  }
+  return true;
+}

Adafruit_OPT4048.h

@@ -0,0 +1,58 @@
+/*
+  This is a library for the OPT4048 ambient light sensor
+  Designed to work with Adafruit BusIO: https://github.com/adafruit/Adafruit_BusIO
+
+  Written by Adafruit Industries, 2025.
+*/
+
+#ifndef ADAFRUIT_OPT4048_H
+#define ADAFRUIT_OPT4048_H
+
+#include "Arduino.h"
+#include <Wire.h>
+#include <Adafruit_I2CDevice.h>
+#include <Adafruit_BusIO_Register.h>
+
+// Default I2C address (ADDR pin connected to GND)
+#define OPT4048_DEFAULT_ADDR        0x44
+
+// Register addresses
+#define OPT4048_REG_CH0_MSB         0x00
+#define OPT4048_REG_CH0_LSB         0x01
+#define OPT4048_REG_CH1_MSB         0x02
+#define OPT4048_REG_CH1_LSB         0x03
+#define OPT4048_REG_CH2_MSB         0x04
+#define OPT4048_REG_CH2_LSB         0x05
+#define OPT4048_REG_CH3_MSB         0x06
+#define OPT4048_REG_CH3_LSB         0x07
+#define OPT4048_REG_THRESHOLD_LOW   0x08
+#define OPT4048_REG_THRESHOLD_HIGH  0x09
+#define OPT4048_REG_CONFIG          0x0A
+#define OPT4048_REG_THRESHOLD_CFG   0x0B
+#define OPT4048_REG_STATUS          0x0C
+#define OPT4048_REG_DEVICE_ID       0x11
+
+/**
+  @brief  Class that stores state and functions for interacting with the OPT4048 sensor.
+*/
+class Adafruit_OPT4048 {
+public:
+  Adafruit_OPT4048();
+  ~Adafruit_OPT4048();
+
+  /**
+   * @brief  Initialize the sensor with given I2C address and Wire instance
+   *
+   * @param  addr I2C address, defaults to OPT4048_DEFAULT_ADDR
+   * @param  wire Pointer to TwoWire instance, defaults to &Wire
+   * @return true on success, false on failure
+   */
+  bool begin(uint8_t addr = OPT4048_DEFAULT_ADDR, TwoWire *wire = &Wire);
+  /** Read all four channels, verify CRC, and return raw ADC code values */
+  bool getChannels(float *ch0, float *ch1, float *ch2, float *ch3);
+
+private:
+  Adafruit_I2CDevice *i2c_dev;
+};
+
+#endif // ADAFRUIT_OPT4048_H

examples/test_opt4048/test_opt4048.ino

@@ -0,0 +1,29 @@
+/*
+  test_opt4048.ino
+  Example sketch for OPT4048 ambient light sensor
+*/
+
+#include <Wire.h>
+#include "Adafruit_OPT4048.h"
+
+Adafruit_OPT4048 sensor;
+
+void setup() {
+  Serial.begin(115200);
+  while (!Serial) {
+    delay(10);
+  }
+  Serial.println("OPT4048 Test");
+  if (!sensor.begin()) {
+    Serial.println("Failed to find OPT4048 chip");
+    while (1) {
+      delay(10);
+    }
+  }
+  Serial.println("OPT4048 found!");
+}
+
+void loop() {
+  // Nothing to do (testing only initialization)
+  delay(1000);
+}