C++ TwoWire::receive方法代码示例

static void read16(byte reg, uint16_t *value)
{
  Wire1.beginTransmission((uint8_t)BMP085_ADDRESS);
  #if ARDUINO >= 100
    Wire1.write((uint8_t)reg);
  #else
    Wire1.send(reg);
  #endif
  Wire1.endTransmission();
  Wire1.requestFrom((uint8_t)BMP085_ADDRESS, (byte)2);
  #if ARDUINO >= 100
    *value = (Wire1.read() << 8) | Wire1.read();
  #else
    *value = (Wire1.receive() << 8) | Wire1.receive();
  #endif
  Wire1.endTransmission();
}

/** Read multiple bytes from an 8-bit device register.
 * @param useSPI  true : use SPI 
 * @param devAddr I2C slave device address
 * @param regAddr First register regAddr to read from
 * @param length Number of bytes to read
 * @param data Buffer to store read data in
 * @param timeout Optional read timeout in milliseconds (0 to disable, leave off to use default class value in I2Cdev::readTimeout)
 * @return Number of bytes read (0 indicates failure)
 */
int8_t I2Cdev::readBytes(bool useSPI, uint8_t devAddr, uint8_t regAddr, uint8_t length, uint8_t *data, uint16_t timeout) {
    #ifdef I2CDEV_SERIAL_DEBUG
        Serial.print(useSPI ? "SPI (0x" : "I2C 0x");
        Serial.print(devAddr, HEX);
        Serial.print(") reading ");
        Serial.print(length, DEC);
        Serial.print(" bytes from 0x");
        Serial.print(regAddr, HEX);
        Serial.print("...");
    #endif
    int8_t count = 0;
	// I2C
	if (!useSPI) {
		Wire.beginTransmission(devAddr);
		#if ((I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE && ARDUINO < 100) || I2CDEV_IMPLEMENTATION == I2CDEV_BUILTIN_NBWIRE)
			Wire.send(regAddr);
		#elif (I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE && ARDUINO >= 100)
			Wire.write(regAddr);
		#endif
		Wire.endTransmission();
		Wire.beginTransmission(devAddr);
		Wire.requestFrom(devAddr, length);

		uint32_t t1 = millis();
		for (; Wire.available() && (timeout == 0 || millis() - t1 < timeout); count++) {
			#if ((I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE && ARDUINO < 100) || I2CDEV_IMPLEMENTATION == I2CDEV_BUILTIN_NBWIRE)
				data[count] = Wire.receive();
			#elif (I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE && ARDUINO >= 100)
				data[count] = Wire.read();
			#endif
			#ifdef I2CDEV_SERIAL_DEBUG
				Serial.print(data[count], HEX);
				if (count + 1 < length) Serial.print(" ");
			#endif
		}
		if (timeout > 0 && millis() - t1 >= timeout && count < length) count = -1; // timeout
		Wire.endTransmission();
	} else {
	    digitalWrite(devAddr, LOW);
		byte Addr = regAddr | 0x80;
		SPI.transfer(Addr);
		for (uint8_t cnt=0; cnt < length; cnt++) {
			data[cnt] = SPI.transfer(0);
			count++;
		}
		digitalWrite(devAddr, HIGH);
	}
    #ifdef I2CDEV_SERIAL_DEBUG
        Serial.print(". Done (");
        Serial.print(count, DEC);
        Serial.println(" read).");
    #endif
    return count;
}

/** Read multiple bytes from an 8-bit device register.
 * @param devAddr I2C slave device address
 * @param regAddr First register regAddr to read from
 * @param length Number of bytes to read
 * @param data Buffer to store read data in
 * @param timeout Optional read timeout in milliseconds (0 to disable, leave off to use default class value in I2Cdev::readTimeout)
 * @return Number of bytes read (0 indicates failure)
 */
int8_t I2Cdev::readBytes(uint8_t devAddr, uint8_t regAddr, uint8_t length, uint8_t *data, uint16_t timeout) {
    #ifdef I2CDEV_SERIAL_DEBUG
        Serial.print("I2C (0x");
        Serial.print(devAddr, HEX);
        Serial.print(") reading ");
        Serial.print(length, DEC);
        Serial.print(" bytes from 0x");
        Serial.print(regAddr, HEX);
        Serial.print("...");
    #endif

    int8_t count = 0;

    Wire.beginTransmission(devAddr);
    #if ((I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE && ARDUINO < 100) || I2CDEV_IMPLEMENTATION == I2CDEV_BUILTIN_NBWIRE)
        Wire.send(regAddr);
    #elif (I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE && ARDUINO >= 100)
        Wire.write(regAddr);
    #endif
    Wire.endTransmission();

    Wire.beginTransmission(devAddr);
    Wire.requestFrom(devAddr, length);

    uint32_t t1 = millis();
    for (; Wire.available() && (timeout == 0 || millis() - t1 < timeout); count++) {
        #if ((I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE && ARDUINO < 100) || I2CDEV_IMPLEMENTATION == I2CDEV_BUILTIN_NBWIRE)
            data[count] = Wire.receive();
        #elif (I2CDEV_IMPLEMENTATION == I2CDEV_ARDUINO_WIRE && ARDUINO >= 100)
            data[count] = Wire.read();
        #endif
        #ifdef I2CDEV_SERIAL_DEBUG
            Serial.print(data[count], HEX);
            if (count + 1 < length) Serial.print(" ");
        #endif
    }
    if (timeout > 0 && millis() - t1 >= timeout && count < length) count = -1; // timeout

    Wire.endTransmission();

    #ifdef I2CDEV_SERIAL_DEBUG
        Serial.print(". Done (");
        Serial.print(count, DEC);
        Serial.println(" read).");
    #endif

    return count;
}

uint8_t MCP23018_READ(uint8_t device, uint8_t reg)
{
	uint8_t addr;
	uint8_t result;

	if(DEV_MISC == device){ addr = MISC_ADDR; }
	else{ addr = VEH_IO_ADDR; }

	i2c.beginTransmission(addr);
	i2c.write(reg);  				// IODIRA.BANK1 Address
	i2c.endTransmission();

	i2c.requestFrom(addr,(uint8_t)1u);
	while (i2c.available() < 1u);
	result = i2c.receive();

	return result;
}