*/
generic module SoftwareI2CPacketC(int speed)
{
- provides interface I2CPacket<TI2CBasicAddr>;
-
- uses interface GeneralIO as SDA;
- uses interface GeneralIO as SCL;
- uses interface BusyWait<TMicro, uint16_t>;
+ provides interface I2CPacket<TI2CBasicAddr>;
+
+ uses interface GeneralIO as SDA;
+ uses interface GeneralIO as SCL;
+ uses interface BusyWait<TMicro, uint16_t>;
}
implementation
{
- enum
+ 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
{
- 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)
- {
- 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()
+ if (m_state == S_IDLE)
+ {
+ m_state = S_BUSY;
+ }
+ else
+ {
+ return EBUSY;
+ }
+ }
+ atomic
{
- uint16_t addr;
- uint8_t length;
- uint8_t* data;
- error_t error;
- bool read;
- atomic
+ if (flags & I2C_START)
+ {
+ error = ecombine(error, i2cStartCond());
+ error = ecombine(error, i2cTx(addr+1));
+ }
+
+ // Only read data from the device if length is >0.
+ // TODO(henrik): Should a data length of 0 be a invalid input?
+ if (length > 0)
+ {
+ // Read the data from the device.
+ for (i = 0; i < length-1; ++i)
{
- addr = m_addr;
- length = m_length;
- data = m_data;
- error = m_error;
- m_state = S_IDLE;
- read = m_read;
+ data[i] = i2cRx(false);
}
- if (read)
+ if (flags & I2C_ACK_END)
{
- signal I2CPacket.readDone(error, addr, length, data);
+ data[length-1] = i2cRx(false);
}
else
{
- signal I2CPacket.writeDone(error, addr, length, data);
+ data[length-1] = i2cRx(true);
}
+ }
+ if (flags & I2C_STOP)
+ {
+ error = ecombine(error, i2cStopCond());
+ }
+
+ m_error = error;
+ m_addr = addr;
+ m_length = length;
+ m_data = data;
+ m_read = true;
}
-
- 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
- {
- if (m_state == S_IDLE)
- {
- m_state = S_BUSY;
- }
- else
- {
- return EBUSY;
- }
- }
- atomic
- {
- if (flags & I2C_START)
- {
- error = ecombine(error, i2cStartCond());
- error = ecombine(error, i2cTx(addr+1));
- }
-
- // Only read data from the device if length is >0.
- // TODO(henrik): Should a data length of 0 be a invalid input?
- if (length > 0)
- {
- // Read the data from the device.
- for (i = 0; i < length-1; ++i)
- {
- data[i] = i2cRx(false);
- }
- if (flags & I2C_ACK_END)
- {
- data[length-1] = i2cRx(false);
- }
- else
- {
- data[length-1] = i2cRx(true);
- }
- }
- if (flags & I2C_STOP)
- {
- error = ecombine(error, i2cStopCond());
- }
-
- m_error = error;
- m_addr = addr;
- m_length = length;
- m_data = data;
- m_read = true;
- }
- post signalTask();
+ post signalTask();
- return SUCCESS;
- }
+ return SUCCESS;
+ }
- async command error_t I2CPacket.write(i2c_flags_t flags, uint16_t addr, uint8_t length, uint8_t* data)
- {
- uint8_t i;
- error_t error = SUCCESS;
-
- atomic
- {
- if (m_state == S_IDLE)
- {
- m_state = S_BUSY;
- }
- else
- {
- return EBUSY;
- }
- }
- atomic
- {
- if (flags & I2C_START)
- {
- error = ecombine(error, i2cStartCond());
- }
-
- i2cTx(addr);
-
- // Send the data to the device.
- for (i = 0; i < length; ++i)
- {
- error = ecombine(error, i2cTx(data[i]));
- }
-
- if (flags & I2C_STOP)
- {
- error = ecombine(error, i2cStopCond());
- }
-
- m_error = error;
- m_addr = addr;
- m_length = length;
- m_data = data;
- m_read = false;
- }
- post signalTask();
- return SUCCESS;
- }
-}
\ No newline at end of file
+ async command error_t I2CPacket.write(i2c_flags_t flags, uint16_t addr, uint8_t length, uint8_t* data)
+ {
+ uint8_t i;
+ error_t error = SUCCESS;
+
+ atomic
+ {
+ if (m_state == S_IDLE)
+ {
+ m_state = S_BUSY;
+ }
+ else
+ {
+ return EBUSY;
+ }
+ }
+ atomic
+ {
+ if (flags & I2C_START)
+ {
+ error = ecombine(error, i2cStartCond());
+ }
+
+ i2cTx(addr);
+
+ // Send the data to the device.
+ for (i = 0; i < length; ++i)
+ {
+ error = ecombine(error, i2cTx(data[i]));
+ }
+
+ if (flags & I2C_STOP)
+ {
+ error = ecombine(error, i2cStopCond());
+ }
+
+ m_error = error;
+ m_addr = addr;
+ m_length = length;
+ m_data = data;
+ m_read = false;
+ }
+ post signalTask();
+ return SUCCESS;
+ }
+}
projects / tinyos-2.x.git / blobdiff