+ enum
+ {
+ S_IDLE,
+ S_BUSY,
+ };
+
+ uint8_t m_state = S_IDLE;
+ uint16_t m_addr;
+ uint8_t m_length;
+ uint8_t* m_data;
+ error_t m_error;
+ bool m_read;
+
+ uint8_t READSDA()
+ {
+ call SDA.makeInput();
+ return call SDA.get();
+ }
+
+ uint8_t READSCL()
+ {
+ call SCL.makeInput();
+ return call SCL.get();
+ }
+
+ void CLRSCL()
+ {
+ call SCL.clr();
+ call SCL.makeOutput();
+ }
+
+ void CLRSDA()
+ {
+ call SDA.clr();
+ call SDA.makeOutput();
+ }
+
+ void i2cDelay(uint16_t u) {
+ call BusyWait.wait(u);
+ }
+
+ uint8_t i2cReadBit(void)
+ {
+ uint8_t bit;
+
+ /* lets the slave drive data */
+ READSDA();
+ i2cDelay(speed/2);
+ /* Clock stretching */
+ while (READSCL() == 0);
+ /* SCL is high, now data is valid */
+ bit = READSDA();
+ i2cDelay(speed/2);
+ CLRSCL();
+ return bit;
+ }
+
+ error_t i2cWriteBit(bool bit)
+ {
+ if (bit)
+ READSDA();
+ else
+ CLRSDA();
+ i2cDelay(speed/2);
+ /* Clock stretching */
+ while (READSCL() == 0);
+ /* SCL is high, now data is valid */
+ /* check that nobody is driving SDA */
+ if (bit && READSDA() == 0)
+ return FAIL;
+ i2cDelay(speed/2);
+ CLRSCL();
+ return SUCCESS;
+ }
+
+ error_t i2cStartCond(void)
+ {
+ READSCL();
+ if (READSDA() == 0)
+ return FAIL;
+ /* SCL is high, set SDA from 1 to 0 */
+ CLRSDA();
+ i2cDelay(speed/2);
+ CLRSCL();
+ return SUCCESS;
+ }
+
+ error_t i2cStopCond(void)
+ {
+ /* set SDA to 0 */
+ CLRSDA();
+ i2cDelay(speed/2);
+ /* Clock stretching */
+ while (READSCL() == 0);
+ /* SCL is high, set SDA from 0 to 1 */
+ if (READSDA() == 0)
+ return FAIL;
+ i2cDelay(speed/2);
+ return SUCCESS;
+ }
+
+ error_t i2cTx(uint8_t byte)
+ {
+ uint8_t bit;
+ uint8_t ack;
+ error_t error = SUCCESS;
+
+ for (bit = 0; bit < 8; bit++) {
+ error = ecombine(error, i2cWriteBit(byte & 0x80));
+ byte <<= 1;
+ }
+
+ // The ack bit is 0 for success
+ if (!i2cReadBit())
+ {
+ return ecombine(error, SUCCESS);
+ }
+ else
+ {
+ return FAIL;
+ }
+ }
+
+ uint8_t i2cRx (bool nack)
+ {
+ uint8_t byte = 0;
+ uint8_t bit;
+
+ for (bit = 0; bit < 8; bit++) {
+ byte <<= 1;
+ byte |= i2cReadBit();
+ }
+ i2cWriteBit(nack);
+ return byte;
+ }
+
+ task void signalTask()
+ {
+ uint16_t addr;
+ uint8_t length;
+ uint8_t* data;
+ error_t error;
+ bool read;
+ atomic
+ {
+ addr = m_addr;
+ length = m_length;
+ data = m_data;
+ error = m_error;
+ m_state = S_IDLE;
+ read = m_read;
+ }
+ if (read)
+ {
+ signal I2CPacket.readDone(error, addr, length, data);
+ }
+ else
+ {
+ signal I2CPacket.writeDone(error, addr, length, data);
+ }
+ }
+
+ async command error_t I2CPacket.read(i2c_flags_t flags, uint16_t addr, uint8_t length, uint8_t* data)
+ {
+ uint8_t i;
+ error_t error = SUCCESS;
+
+ // Both I2C_STOP and I2C_ACK_END flags are not allowed at the same time.
+ if ((flags & I2C_STOP) && (flags & I2C_ACK_END))
+ {
+ return EINVAL;
+ }
+
+ atomic