314 lines
9 KiB
C++
314 lines
9 KiB
C++
#include "Adafruit_I2CDevice.h"
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//#define DEBUG_SERIAL Serial
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/*!
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* @brief Create an I2C device at a given address
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* @param addr The 7-bit I2C address for the device
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* @param theWire The I2C bus to use, defaults to &Wire
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*/
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Adafruit_I2CDevice::Adafruit_I2CDevice(uint8_t addr, TwoWire *theWire) {
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_addr = addr;
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_wire = theWire;
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_begun = false;
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#ifdef ARDUINO_ARCH_SAMD
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_maxBufferSize = 250; // as defined in Wire.h's RingBuffer
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#elif defined(ESP32)
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_maxBufferSize = I2C_BUFFER_LENGTH;
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#else
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_maxBufferSize = 32;
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#endif
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}
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/*!
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* @brief Initializes and does basic address detection
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* @param addr_detect Whether we should attempt to detect the I2C address
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* with a scan. 99% of sensors/devices don't mind but once in a while, they spaz
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* on a scan!
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* @return True if I2C initialized and a device with the addr found
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*/
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bool Adafruit_I2CDevice::begin(bool addr_detect) {
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_wire->begin();
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_begun = true;
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if (addr_detect) {
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return detected();
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}
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return true;
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}
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/*!
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* @brief De-initialize device, turn off the Wire interface
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*/
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void Adafruit_I2CDevice::end(void) {
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// Not all port implement Wire::end(), such as
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// - ESP8266
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// - AVR core without WIRE_HAS_END
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// - ESP32: end() is implemented since 2.0.1 which is latest at the moment.
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// Temporarily disable for now to give time for user to update.
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#if !(defined(ESP8266) || \
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(defined(ARDUINO_ARCH_AVR) && !defined(WIRE_HAS_END)) || \
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defined(ARDUINO_ARCH_ESP32))
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_wire->end();
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_begun = false;
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#endif
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}
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/*!
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* @brief Scans I2C for the address - note will give a false-positive
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* if there's no pullups on I2C
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* @return True if I2C initialized and a device with the addr found
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*/
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bool Adafruit_I2CDevice::detected(void) {
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// Init I2C if not done yet
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if (!_begun && !begin()) {
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return false;
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}
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// A basic scanner, see if it ACK's
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_wire->beginTransmission(_addr);
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if (_wire->endTransmission() == 0) {
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#ifdef DEBUG_SERIAL
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DEBUG_SERIAL.println(F("Detected"));
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#endif
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return true;
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}
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#ifdef DEBUG_SERIAL
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DEBUG_SERIAL.println(F("Not detected"));
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#endif
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return false;
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}
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/*!
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* @brief Write a buffer or two to the I2C device. Cannot be more than
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* maxBufferSize() bytes.
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* @param buffer Pointer to buffer of data to write. This is const to
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* ensure the content of this buffer doesn't change.
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* @param len Number of bytes from buffer to write
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* @param prefix_buffer Pointer to optional array of data to write before
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* buffer. Cannot be more than maxBufferSize() bytes. This is const to
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* ensure the content of this buffer doesn't change.
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* @param prefix_len Number of bytes from prefix buffer to write
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* @param stop Whether to send an I2C STOP signal on write
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* @return True if write was successful, otherwise false.
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*/
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bool Adafruit_I2CDevice::write(const uint8_t *buffer, size_t len, bool stop,
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const uint8_t *prefix_buffer,
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size_t prefix_len) {
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if ((len + prefix_len) > maxBufferSize()) {
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// currently not guaranteed to work if more than 32 bytes!
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// we will need to find out if some platforms have larger
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// I2C buffer sizes :/
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#ifdef DEBUG_SERIAL
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DEBUG_SERIAL.println(F("\tI2CDevice could not write such a large buffer"));
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#endif
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return false;
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}
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_wire->beginTransmission(_addr);
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// Write the prefix data (usually an address)
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if ((prefix_len != 0) && (prefix_buffer != nullptr)) {
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if (_wire->write(prefix_buffer, prefix_len) != prefix_len) {
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#ifdef DEBUG_SERIAL
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DEBUG_SERIAL.println(F("\tI2CDevice failed to write"));
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#endif
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return false;
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}
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}
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// Write the data itself
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if (_wire->write(buffer, len) != len) {
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#ifdef DEBUG_SERIAL
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DEBUG_SERIAL.println(F("\tI2CDevice failed to write"));
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#endif
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return false;
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}
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#ifdef DEBUG_SERIAL
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DEBUG_SERIAL.print(F("\tI2CWRITE @ 0x"));
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DEBUG_SERIAL.print(_addr, HEX);
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DEBUG_SERIAL.print(F(" :: "));
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if ((prefix_len != 0) && (prefix_buffer != nullptr)) {
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for (uint16_t i = 0; i < prefix_len; i++) {
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DEBUG_SERIAL.print(F("0x"));
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DEBUG_SERIAL.print(prefix_buffer[i], HEX);
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DEBUG_SERIAL.print(F(", "));
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}
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}
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for (uint16_t i = 0; i < len; i++) {
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DEBUG_SERIAL.print(F("0x"));
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DEBUG_SERIAL.print(buffer[i], HEX);
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DEBUG_SERIAL.print(F(", "));
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if (i % 32 == 31) {
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DEBUG_SERIAL.println();
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}
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}
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if (stop) {
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DEBUG_SERIAL.print("\tSTOP");
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}
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#endif
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if (_wire->endTransmission(stop) == 0) {
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#ifdef DEBUG_SERIAL
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DEBUG_SERIAL.println();
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// DEBUG_SERIAL.println("Sent!");
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#endif
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return true;
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} else {
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#ifdef DEBUG_SERIAL
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DEBUG_SERIAL.println("\tFailed to send!");
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#endif
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return false;
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}
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}
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/*!
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* @brief Read from I2C into a buffer from the I2C device.
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* Cannot be more than maxBufferSize() bytes.
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* @param buffer Pointer to buffer of data to read into
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* @param len Number of bytes from buffer to read.
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* @param stop Whether to send an I2C STOP signal on read
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* @return True if read was successful, otherwise false.
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*/
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bool Adafruit_I2CDevice::read(uint8_t *buffer, size_t len, bool stop) {
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size_t pos = 0;
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while (pos < len) {
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size_t read_len =
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((len - pos) > maxBufferSize()) ? maxBufferSize() : (len - pos);
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bool read_stop = (pos < (len - read_len)) ? false : stop;
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if (!_read(buffer + pos, read_len, read_stop))
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return false;
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pos += read_len;
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}
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return true;
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}
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bool Adafruit_I2CDevice::_read(uint8_t *buffer, size_t len, bool stop) {
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#if defined(TinyWireM_h)
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size_t recv = _wire->requestFrom((uint8_t)_addr, (uint8_t)len);
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#elif defined(ARDUINO_ARCH_MEGAAVR)
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size_t recv = _wire->requestFrom(_addr, len, stop);
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#else
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size_t recv = _wire->requestFrom((uint8_t)_addr, (uint8_t)len, (uint8_t)stop);
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#endif
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if (recv != len) {
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// Not enough data available to fulfill our obligation!
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#ifdef DEBUG_SERIAL
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DEBUG_SERIAL.print(F("\tI2CDevice did not receive enough data: "));
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DEBUG_SERIAL.println(recv);
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#endif
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return false;
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}
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for (uint16_t i = 0; i < len; i++) {
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buffer[i] = _wire->read();
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}
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#ifdef DEBUG_SERIAL
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DEBUG_SERIAL.print(F("\tI2CREAD @ 0x"));
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DEBUG_SERIAL.print(_addr, HEX);
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DEBUG_SERIAL.print(F(" :: "));
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for (uint16_t i = 0; i < len; i++) {
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DEBUG_SERIAL.print(F("0x"));
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DEBUG_SERIAL.print(buffer[i], HEX);
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DEBUG_SERIAL.print(F(", "));
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if (len % 32 == 31) {
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DEBUG_SERIAL.println();
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}
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}
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DEBUG_SERIAL.println();
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#endif
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return true;
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}
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/*!
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* @brief Write some data, then read some data from I2C into another buffer.
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* Cannot be more than maxBufferSize() bytes. The buffers can point to
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* same/overlapping locations.
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* @param write_buffer Pointer to buffer of data to write from
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* @param write_len Number of bytes from buffer to write.
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* @param read_buffer Pointer to buffer of data to read into.
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* @param read_len Number of bytes from buffer to read.
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* @param stop Whether to send an I2C STOP signal between the write and read
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* @return True if write & read was successful, otherwise false.
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*/
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bool Adafruit_I2CDevice::write_then_read(const uint8_t *write_buffer,
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size_t write_len, uint8_t *read_buffer,
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size_t read_len, bool stop) {
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if (!write(write_buffer, write_len, stop)) {
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return false;
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}
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return read(read_buffer, read_len);
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}
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/*!
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* @brief Returns the 7-bit address of this device
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* @return The 7-bit address of this device
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*/
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uint8_t Adafruit_I2CDevice::address(void) { return _addr; }
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/*!
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* @brief Change the I2C clock speed to desired (relies on
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* underlying Wire support!
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* @param desiredclk The desired I2C SCL frequency
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* @return True if this platform supports changing I2C speed.
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* Not necessarily that the speed was achieved!
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*/
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bool Adafruit_I2CDevice::setSpeed(uint32_t desiredclk) {
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#if defined(__AVR_ATmega328__) || \
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defined(__AVR_ATmega328P__) // fix arduino core set clock
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// calculate TWBR correctly
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if ((F_CPU / 18) < desiredclk) {
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#ifdef DEBUG_SERIAL
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Serial.println(F("I2C.setSpeed too high."));
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#endif
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return false;
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}
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uint32_t atwbr = ((F_CPU / desiredclk) - 16) / 2;
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if (atwbr > 16320) {
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#ifdef DEBUG_SERIAL
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Serial.println(F("I2C.setSpeed too low."));
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#endif
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return false;
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}
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if (atwbr <= 255) {
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atwbr /= 1;
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TWSR = 0x0;
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} else if (atwbr <= 1020) {
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atwbr /= 4;
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TWSR = 0x1;
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} else if (atwbr <= 4080) {
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atwbr /= 16;
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TWSR = 0x2;
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} else { // if (atwbr <= 16320)
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atwbr /= 64;
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TWSR = 0x3;
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}
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TWBR = atwbr;
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#ifdef DEBUG_SERIAL
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Serial.print(F("TWSR prescaler = "));
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Serial.println(pow(4, TWSR));
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Serial.print(F("TWBR = "));
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Serial.println(atwbr);
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#endif
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return true;
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#elif (ARDUINO >= 157) && !defined(ARDUINO_STM32_FEATHER) && \
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!defined(TinyWireM_h)
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_wire->setClock(desiredclk);
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return true;
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#else
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(void)desiredclk;
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return false;
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#endif
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}
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