/*! \brief TWI slave write interrupt handler.
*
* Handles TWI slave write transactions and responses.
*
* \param twi The TWI_Slave_t struct instance.
*/
void TWI_SlaveWriteHandler(TWI_Slave_t *twi)
{
/* If NACK, slave write transaction finished. */
if ((twi->bytesSent > 0) && (twi->interface->SLAVE.STATUS &
TWI_SLAVE_RXACK_bm)) {
twi->interface->SLAVE.CTRLB = TWI_SLAVE_CMD_COMPTRANS_gc;
TWI_SlaveTransactionFinished(twi, TWIS_RESULT_OK);
}
/* If ACK, master expects more data. */
else {
if (twi->bytesSent < TWIS_SEND_BUFFER_SIZE) {
uint8_t data = twi->sendData[twi->bytesSent];
twi->interface->SLAVE.DATA = data;
twi->bytesSent++;
/* Send data, wait for data interrupt. */
twi->interface->SLAVE.CTRLB = TWI_SLAVE_CMD_RESPONSE_gc;
}
/* If buffer overflow. */
else {
twi->interface->SLAVE.CTRLB = TWI_SLAVE_CMD_COMPTRANS_gc;
TWI_SlaveTransactionFinished(twi, TWIS_RESULT_BUFFER_OVERFLOW);
}
}
}
/**************************************************************************//**
\brief TWI slave read interrupt handler.
Handles TWI slave read transactions and responses.
\param twi The TWI_Slave_t struct instance.
******************************************************************************/
static void TWI_SlaveReadHandler(TWI_Slave_t *twi)
{
/* Enable stop interrupt. */
uint8_t currentCtrlA = twi->interface->SLAVE.CTRLA;
twi->interface->SLAVE.CTRLA = currentCtrlA | TWI_SLAVE_PIEN_bm;
/* If free space in buffer. */
if (twi->bytesReceived < TWIS_RECEIVE_BUFFER_SIZE) {
/* Fetch data */
uint8_t data = twi->interface->SLAVE.DATA;
twi->receivedData[twi->bytesReceived] = data;
twi->bytesReceived++;
/* If application signalling need to abort (error occured),
* complete transaction and wait for next START. Otherwise
* send ACK and wait for data interrupt.
*/
if (twi->abort) {
twi->interface->SLAVE.CTRLB = TWI_SLAVE_CMD_COMPTRANS_gc;
TWI_SlaveTransactionFinished(twi, TWIS_RESULT_ABORTED);
twi->abort = false;
} else {
twi->interface->SLAVE.CTRLB = TWI_SLAVE_CMD_RESPONSE_gc;
}
}
/* If buffer overflow, send NACK and wait for next START. Set
* result buffer overflow.
*/
else {
twi->interface->SLAVE.CTRLB = TWI_SLAVE_ACKACT_bm |
TWI_SLAVE_CMD_COMPTRANS_gc;
TWI_SlaveTransactionFinished(twi, TWIS_RESULT_BUFFER_OVERFLOW);
}
}
/*! \brief TWI stop condition interrupt handler.
*
* \param twi The TWI_Slave_t struct instance.
*/
static void TWI_SlaveStopHandler(TWI_Slave_t *twi)
{
/* Disable stop interrupt. */
uint8_t currentCtrlA = twi->interface->SLAVE.CTRLA;
twi->interface->SLAVE.CTRLA = currentCtrlA & ~TWI_SLAVE_PIEN_bm;
uint8_t currentStatus = twi->interface->SLAVE.STATUS;
twi->interface->SLAVE.STATUS = currentStatus | TWI_SLAVE_APIF_bm;
TWI_SlaveTransactionFinished(twi, TWIS_RESULT_OK);
}
/*! \brief TWI slave write interrupt handler.
*
* Handles TWI slave write transactions and responses.
*
* \param twi The TWI_Slave_t struct instance.
*/
static void TWI_SlaveWriteHandler(TWI_Slave_t *twi)
{
/* If NACK, slave write transaction finished. */
if ((twi->bytesSent > 0) && (twic_status_reg & TWI_SLAVE_RXACK_bm)) {
//init first byte to write
twic_data_reg = twi->sendData[0];
TWI_SlaveTransactionFinished(twi, TWIS_RESULT_OK);
}
/* If ACK, master expects more data. */
else {
if (twi->bytesSent < TWIS_SEND_BUFFER_SIZE) {
twi->bytesSent++;
uint8_t data = twi->sendData[twi->bytesSent];
twic_data_reg = data;
}
else {
/* If buffer overflow. */
TWI_SlaveTransactionFinished(twi, TWIS_RESULT_BUFFER_OVERFLOW);
}
}
}
/*! \brief TWI stop condition interrupt handler.
*
* \param twi The TWI_Slave_t struct instance.
*/
void TWI_SlaveStopHandler(TWI_Slave_t * twi)
{
/* Disable stop interrupt. */
uint8_t currentCtrlA = twi->interface->SLAVE.CTRLA;
twi->interface->SLAVE.CTRLA = currentCtrlA & ~TWI_SLAVE_PIEN_bm;
/* Clear APIF, according to flowchart don't ACK or NACK */
uint8_t currentStatus = twi->interface->SLAVE.STATUS;
twi->interface->SLAVE.STATUS = currentStatus | TWI_SLAVE_APIF_bm;
TWI_SlaveTransactionFinished(twi, TWIS_RESULT_OK);
}
/*! \brief Common TWI slave interrupt service routine.
*
* Handles all TWI transactions and responses to address match, data reception,
* data transmission, bus error and data collision.
*
* \param twi The TWI_Slave_t struct instance.
*/
void TWI_SlaveInterruptHandler(TWI_Slave_t *twi)
{
//static uint8_t sent_NACK = 0; //!< Holds whether NACK has been transmitted
uint8_t currentStatus = twi->interface->SLAVE.STATUS;
twi->interface->SLAVE.CTRLB &= ~TWI_SLAVE_ACKACT_bm; //!< Clear ACKACT
/* If bus error. */
if (currentStatus & TWI_SLAVE_BUSERR_bm) {
twi->bytesReceived = 0;
twi->bytesSent = 0;
twi->result = TWIS_RESULT_BUS_ERROR;
twi->status = TWIS_STATUS_READY;
}
/* If transmit collision. */
else if (currentStatus & TWI_SLAVE_COLL_bm) {
twi->bytesReceived = 0;
twi->bytesSent = 0;
twi->result = TWIS_RESULT_TRANSMIT_COLLISION;
twi->status = TWIS_STATUS_READY;
}
/* If address match. */
else if ((currentStatus & TWI_SLAVE_APIF_bm) &&
(currentStatus & TWI_SLAVE_AP_bm)) {
TWI_SlaveAddressMatchHandler(twi);
}
/* If stop (only enabled through slave read transaction). */
else if (currentStatus & TWI_SLAVE_APIF_bm) {
TWI_SlaveStopHandler(twi);
}
/* If data interrupt. */
else if (currentStatus & TWI_SLAVE_DIF_bm) {
TWI_SlaveDataHandler(twi);
}
/* If unexpected state. */
else {
TWI_SlaveTransactionFinished(twi, TWIS_RESULT_FAIL);
}
}
/**************************************************************************//**
\brief TWI stop condition interrupt handler.
\param twi The TWI_Slave_t struct instance.
******************************************************************************/
static void TWI_SlaveStopHandler(TWI_Slave_t *twi)
{
/* Disable stop interrupt. */
uint8_t currentCtrlA = twi->interface->SLAVE.CTRLA;
twi->interface->SLAVE.CTRLA = currentCtrlA & ~TWI_SLAVE_PIEN_bm;
/* Clear APIF, according to flowchart don't ACK or NACK */
uint8_t currentStatus = twi->interface->SLAVE.STATUS;
twi->interface->SLAVE.STATUS = currentStatus | TWI_SLAVE_APIF_bm;
// Process the received data.
TwiDataParser(twiSlave);
TWI_SlaveTransactionFinished(twi, TWIS_RESULT_OK);
// Flush the buffers used.
flush_Twibuffer();
}
/*! \brief TWI address match interrupt handler.
*
* Prepares TWI module for transaction when an address match occures.
*
* \param twi The TWI_Slave_t struct instance.
*/
void TWI_SlaveAddressMatchHandler(TWI_Slave_t *twi)
{
/* If application signalling need to abort (error occured). */
if (twi->abort) {
twi->interface->SLAVE.CTRLB = TWI_SLAVE_CMD_COMPTRANS_gc;
TWI_SlaveTransactionFinished(twi, TWIS_RESULT_ABORTED);
twi->abort = false;
} else {
twi->status = TWIS_STATUS_BUSY;
twi->result = TWIS_RESULT_UNKNOWN;
/* Disable stop interrupt. */
uint8_t currentCtrlA = twi->interface->SLAVE.CTRLA;
twi->interface->SLAVE.CTRLA = currentCtrlA & ~TWI_SLAVE_PIEN_bm;
twi->bytesReceived = 0;
twi->bytesSent = 0;
/* Send ACK, wait for data interrupt. */
twi->interface->SLAVE.CTRLB = TWI_SLAVE_CMD_RESPONSE_gc;
}
}
