void TwoWire::onService(void) {
// Retrieve interrupt status
uint32_t sr = twi_get_interrupt_status(twi);
if (status == SLAVE_IDLE && TWI_STATUS_SVACC(sr)) {
twi_disable_interrupt(twi, TWI_IDR_SVACC);
twi_enable_interrupt(twi, TWI_IER_RXRDY | TWI_IER_GACC | TWI_IER_NACK
| TWI_IER_EOSACC | TWI_IER_SCL_WS | TWI_IER_TXCOMP);
srvBufferLength = 0;
srvBufferIndex = 0;
// Detect if we should go into RECV or SEND status
// SVREAD==1 means *master* reading -> SLAVE_SEND
if (!TWI_STATUS_SVREAD(sr)) {
status = SLAVE_RECV;
} else {
status = SLAVE_SEND;
// Alert calling program to generate a response ASAP
if (onRequestCallback)
onRequestCallback();
else
// create a default 1-byte response
write((uint8_t) 0);
}
}
if (status != SLAVE_IDLE) {
if (TWI_STATUS_TXCOMP(sr) && TWI_STATUS_EOSACC(sr)) {
if (status == SLAVE_RECV && onReceiveCallback) {
// Copy data into rxBuffer
// (allows to receive another packet while the
// user program reads actual data)
for (uint8_t i = 0; i < srvBufferLength; ++i)
rxBuffer[i] = srvBuffer[i];
rxBufferIndex = 0;
rxBufferLength = srvBufferLength;
// Alert calling program
onReceiveCallback( rxBufferLength);
}
// Transfer completed
twi_enable_interrupt(twi, TWI_SR_SVACC);
twi_disable_interrupt(twi, TWI_IDR_RXRDY | TWI_IDR_GACC | TWI_IDR_NACK
| TWI_IDR_EOSACC | TWI_IDR_SCL_WS | TWI_IER_TXCOMP);
status = SLAVE_IDLE;
}
}
if (status == SLAVE_RECV) {
if (TWI_STATUS_RXRDY(sr)) {
if (srvBufferLength < BUFFER_LENGTH)
{
srvBuffer[srvBufferLength++] = twi_read_byte(twi);
}
}
}
if (status == SLAVE_SEND) {
if (TWI_STATUS_TXRDY(sr) && !TWI_STATUS_NACK(sr)) {
uint8_t c = 'x';
if (srvBufferIndex < srvBufferLength)
{
c = srvBuffer[srvBufferIndex++];
}
twi_write_byte(twi, c);
}
}
}
/**
* \brief Interrupt handler for a TWI peripheral. Manages asynchronous transfer
* occuring on the bus. This function MUST be called by the interrupt service
* routine of the TWI peripheral if asynchronous read/write are needed.
* \param pTwid Pointer to a Twid instance.
*/
void TWID_Handler( Twid *pTwid )
{
uint8_t status;
AsyncTwi *pTransfer ;
Twi *pTwi ;
assert( pTwid != NULL ) ;
pTransfer = (AsyncTwi*)pTwid->pTransfer ;
assert( pTransfer != NULL ) ;
pTwi = pTwid->pTwi ;
assert( pTwi != NULL ) ;
/* Retrieve interrupt status */
status = TWI_GetMaskedStatus(pTwi);
/* Byte received */
if (TWI_STATUS_RXRDY(status)) {
pTransfer->pData[pTransfer->transferred] = TWI_ReadByte(pTwi);
pTransfer->transferred++;
/* check for transfer finish */
if (pTransfer->transferred == pTransfer->num) {
TWI_DisableIt(pTwi, TWI_IDR_RXRDY);
TWI_EnableIt(pTwi, TWI_IER_TXCOMP);
}
/* Last byte? */
else if (pTransfer->transferred == (pTransfer->num - 1)) {
TWI_Stop(pTwi);
}
}
/* Byte sent*/
else if (TWI_STATUS_TXRDY(status)) {
/* Transfer finished ? */
if (pTransfer->transferred == pTransfer->num) {
TWI_DisableIt(pTwi, TWI_IDR_TXRDY);
TWI_EnableIt(pTwi, TWI_IER_TXCOMP);
TWI_SendSTOPCondition(pTwi);
}
/* Bytes remaining */
else {
TWI_WriteByte(pTwi, pTransfer->pData[pTransfer->transferred]);
pTransfer->transferred++;
}
}
/* Transfer complete*/
else if (TWI_STATUS_TXCOMP(status)) {
TWI_DisableIt(pTwi, TWI_IDR_TXCOMP);
pTransfer->status = 0;
pTwid->pTransfer = 0;
if (pTransfer->callback) {
pTransfer->callback((Async *) pTransfer);
}
}
}
