/*! \brief TWI master read interrupt handler.
*
* This is the master read interrupt handler that takes care of
* reading bytes from the TWI slave.
*
* \param twi The TWI_Master_t struct instance.
*/
static void TWI_MasterReadHandler()
{
/* Fetch data if bytes to be read. */
if (twi->bytesRead < TWIM_READ_BUFFER_SIZE) {
uint8_t data = twi->interface->MASTER.DATA;
twi->readData[twi->bytesRead] = data;
twi->bytesRead++;
}
/* If buffer overflow, issue STOP and BUFFER_OVERFLOW condition. */
else {
twi->interface->MASTER.CTRLC = TWI_MASTER_CMD_STOP_gc;
TWI_MasterTransactionFinished(TWIM_RESULT_BUFFER_OVERFLOW);
}
/* Local variable used in if test to avoid compiler warning. */
uint8_t bytesToRead = twi->bytesToRead;
/* If more bytes to read, issue ACK and start a byte read. */
if (twi->bytesRead < bytesToRead) {
twi->interface->MASTER.CTRLC = TWI_MASTER_CMD_RECVTRANS_gc;
}
/* If transaction finished, issue NACK and STOP condition. */
else {
twi->interface->MASTER.CTRLC = TWI_MASTER_ACKACT_bm |
TWI_MASTER_CMD_STOP_gc;
TWI_MasterTransactionFinished(TWIM_RESULT_OK);
}
}
/*! \brief TWI master write interrupt handler.
*
* Handles TWI transactions (master write) and responses to (N)ACK.
*
* \param twi The TWI_Master_t struct instance.
*/
static void TWI_MasterWriteHandler()
{
/* Local variables used in if tests to avoid compiler warning. */
uint8_t bytesToWrite = twi->bytesToWrite;
uint8_t bytesToRead = twi->bytesToRead;
/* If NOT acknowledged (NACK) by slave cancel the transaction. */
if (twi->interface->MASTER.STATUS & TWI_MASTER_RXACK_bm) {
twi->interface->MASTER.CTRLC = TWI_MASTER_CMD_STOP_gc;
twi->result = TWIM_RESULT_NACK_RECEIVED;
twi->status = TWIM_STATUS_READY;
}
/* If more bytes to write, send data. */
else if (twi->bytesWritten < bytesToWrite) {
uint8_t data = twi->writeData[twi->bytesWritten];
twi->interface->MASTER.DATA = data;
++twi->bytesWritten;
}
/* If bytes to read, send repeated START condition + Address +
* 'R/_W = 1'
*/
else if (twi->bytesRead < bytesToRead) {
uint8_t readAddress = twi->address | 0x01;
twi->interface->MASTER.ADDR = readAddress;
}
/* If transaction finished, send STOP condition and set RESULT OK. */
else {
twi->interface->MASTER.CTRLC = TWI_MASTER_CMD_STOP_gc;
TWI_MasterTransactionFinished(TWIM_RESULT_OK);
}
}
/*! \brief Common TWI master interrupt service routine.
*
* Check current status and calls the appropriate handler.
*
* \param twi The TWI_Master_t struct instance.
*/
static void TWI_MasterInterruptHandler()
{
uint8_t currentStatus = twi->interface->MASTER.STATUS;
/* If arbitration lost or bus error. */
if ((currentStatus & TWI_MASTER_ARBLOST_bm) ||
(currentStatus & TWI_MASTER_BUSERR_bm)) {
TWI_MasterArbitrationLostBusErrorHandler();
}
/* If master write interrupt. */
else if (currentStatus & TWI_MASTER_WIF_bm) {
TWI_MasterWriteHandler();
}
/* If master read interrupt. */
else if (currentStatus & TWI_MASTER_RIF_bm) {
TWI_MasterReadHandler();
}
/* If unexpected state. */
else {
TWI_MasterTransactionFinished(TWIM_RESULT_FAIL);
}
}
/*============================================================================
Name : TWI_MasterWriteHandler
------------------------------------------------------------------------------
Purpose : Handles TWI
Input : n/a
Output : n/a
Notes : Called from TWI Interrupt routine
============================================================================*/
void TWI_MasterWriteHandler(void)
{
// Local variables used in if tests to avoid compiler warning.
uint16_t bytesToWrite = twiMaster.bytesToWrite;
//uint16_t bytesToRead = twiMaster.bytesToRead;
// If NOT acknowledged (NACK) by slave cancel the transaction.
if (twiMaster.interface->MASTER.STATUS & TWI_MASTER_RXACK_bm) {
twiMaster.interface->MASTER.CTRLC = TWI_MASTER_CMD_STOP_gc;
twiMaster.result = TWIM_RESULT_NACK_RECEIVED;
twiMaster.status = TWIM_STATUS_READY;
}
// If more bytes to write, send data.
else if (twiMaster.bytesWritten <= bytesToWrite)
{
uint8_t data = TX_Buffer[twiMaster.bytesWritten];
twiMaster.interface->MASTER.DATA = data;
++twiMaster.bytesWritten;
}
// If transaction finished, send STOP condition and set RESULT OK.
else {
twiMaster.interface->MASTER.CTRLC = TWI_MASTER_CMD_STOP_gc;
TWI_MasterTransactionFinished(TWIM_RESULT_OK);
}
}
/*============================================================================
Name : TWI_MasterReadHandler
------------------------------------------------------------------------------
Purpose : Handles TWI
Input : n/a
Output : n/a
Notes : Called from TWI Interrupt routine
============================================================================*/
void TWI_MasterReadHandler(void)
{
uint8_t FrameInProgress;
uint8_t data = twiMaster.interface->MASTER.DATA;
FrameInProgress = RxHandler(data);
// If more bytes to read, issue ACK and start a byte read.
if (FrameInProgress)
{
twiMaster.interface->MASTER.CTRLC = TWI_MASTER_CMD_RECVTRANS_gc;
}
else// If transaction finished, issue NACK and STOP condition.
{
twiMaster.interface->MASTER.CTRLC = TWI_MASTER_ACKACT_bm | TWI_MASTER_CMD_STOP_gc;
TWI_MasterTransactionFinished(TWIM_RESULT_OK);
}
}
void WakeUpSensor(TWI_Master_t *twi,
uint8_t address){
// If write command, send the START condition + Address + 'R/_W = 0'
uint8_t writeAddress = twi->address & ~0x01;
twi->interface->MASTER.ADDR = writeAddress;
// If NOT acknowledged (NACK) by slave cancel the transaction.
if (twi->interface->MASTER.STATUS & TWI_MASTER_RXACK_bm) {
twi->interface->MASTER.CTRLC = TWI_MASTER_CMD_STOP_gc;
twi->result = TWIM_RESULT_NACK_RECEIVED;
twi->status = TWIM_STATUS_READY;
}
// If transaction finished, send STOP condition and set RESULT OK.
else {
twi->interface->MASTER.CTRLC = TWI_MASTER_CMD_STOP_gc;
TWI_MasterTransactionFinished(twi, TWIM_RESULT_OK);
}
}
