/**
* Handle a request ISL as a slave
*/
void DWire::_handleRequestSlave( void )
{
// Check whether a user interrupt has been set
if ( !user_onRequest )
return;
// If no message has been set, then call the user interrupt to set
if (!(*pTxBufferIndex))
{
user_onRequest( );
*pTxBufferSize = *pTxBufferIndex - 1;
*pTxBufferIndex = 0;
}
// If we've transmitted the entire message, then reset the tx buffer
if (*pTxBufferIndex > *pTxBufferSize)
{
*pTxBufferIndex = 0;
*pTxBufferSize = 0;
}
else
{
// Transmit a byte
MAP_I2C_slavePutData( module, pTxBuffer[*pTxBufferIndex] );
(*pTxBufferIndex)++;
}
}
// behind the scenes function that is called when data is requested
void TwoWire::onRequestService(void)
{
// don't bother if user hasn't registered a callback
if(!user_onRequest){
return;
}
// alert user program
user_onRequest();
}
// behind the scenes function that is called when data is requested
void WireClass::onRequestService(void){
// don't bother if user hasn't registered a callback
if(!user_onRequest){
return;
}
// reset tx buffer iterator vars
// !!! this will kill any pending pre-master sendTo() activity
txBufferIndex = 0;
txBufferLength = 0;
// alert user program
user_onRequest();
}
void TwoWire::I2CIntHandler(void) {
//clear data interrupt
HWREG(SLAVE_BASE + I2C_O_SICR) = I2C_SICR_DATAIC;
uint8_t startDetected = 0;
uint8_t stopDetected = 0;
if(HWREG(SLAVE_BASE + I2C_O_SRIS) & I2C_SLAVE_INT_START) {
startDetected = 1;
//clear raw start interrupt
HWREG(SLAVE_BASE + I2C_O_SICR) = I2C_SICR_STARTIC;
}
else if(HWREG(SLAVE_BASE + I2C_O_SRIS) & I2C_SLAVE_INT_STOP) {
stopDetected = 1;
HWREG(SLAVE_BASE + I2C_O_SICR) = I2C_SICR_STOPIC;
}
switch(I2CSlaveStatus(SLAVE_BASE) & (I2C_SCSR_TREQ | I2C_SCSR_RREQ)) {
case(I2C_SLAVE_ACT_RREQ)://data received
if(I2CSlaveStatus(SLAVE_BASE) & I2C_SCSR_FBR)
currentState = SLAVE_RX;
if(!RX_BUFFER_FULL) {
rxBuffer[rxWriteIndex] = I2CSlaveDataGet(SLAVE_BASE);
rxWriteIndex = (rxWriteIndex + 1) % BUFFER_LENGTH;
}
break;
case(I2C_SLAVE_ACT_TREQ)://data requested
if(startDetected) {
uint8_t oldWriteIndex = txWriteIndex;
user_onRequest();
//
// send data if onRequest() wrote data that has
// yet to be sent
//
if(oldWriteIndex != txWriteIndex) {
I2CSlaveDataPut(SLAVE_BASE, txBuffer[txReadIndex]);
txReadIndex = (txReadIndex + 1) % BUFFER_LENGTH;
}
}
else if(!TX_BUFFER_EMPTY) {
I2CSlaveDataPut(SLAVE_BASE, txBuffer[txReadIndex]);
txReadIndex = (txReadIndex + 1) % BUFFER_LENGTH;
}
else
I2CSlaveDataPut(SLAVE_BASE, 0);
break;
default:
break;
}
if(stopDetected && currentState == SLAVE_RX) {
int avail = available();
user_onReceive(avail);
currentState = IDLE;
}
}
void TwoWire::isr(void)
{
uint8_t status, c1, data;
static uint8_t receiving=0;
status = port().S;
//serial_print(".");
if (status & I2C_S_ARBL) {
// Arbitration Lost
port().S = I2C_S_ARBL;
//serial_print("a");
if (receiving && rxBufferLength > 0) {
// TODO: does this detect the STOP condition in slave receive mode?
}
if (!(status & I2C_S_IAAS)) return;
}
if (status & I2C_S_IAAS) {
//serial_print("\n");
// Addressed As A Slave
if (status & I2C_S_SRW) {
//serial_print("T");
// Begin Slave Transmit
receiving = 0;
txBufferLength = 0;
if (user_onRequest != NULL) {
user_onRequest();
}
if (txBufferLength == 0) {
// is this correct, transmitting a single zero
// when we should send nothing? Arduino's AVR
// implementation does this, but is it ok?
txBufferLength = 1;
txBuffer[0] = 0;
}
port().C1 = I2C_C1_IICEN | I2C_C1_IICIE | I2C_C1_TX;
port().D = txBuffer[0];
txBufferIndex = 1;
} else {
// Begin Slave Receive
//serial_print("R");
receiving = 1;
rxBufferLength = 0;
port().C1 = I2C_C1_IICEN | I2C_C1_IICIE;
data = port().D;
}
port().S = I2C_S_IICIF;
return;
}
#if defined(WIRE_HAS_STOP_INTERRUPT)
c1 = port().FLT;
if ((c1 & I2C_FLT_STOPF) && (c1 & I2C_FLT_STOPIE)) {
port().FLT = c1 & ~I2C_FLT_STOPIE;
if (user_onReceive != NULL) {
rxBufferIndex = 0;
user_onReceive(rxBufferLength);
}
}
#endif
c1 = port().C1;
if (c1 & I2C_C1_TX) {
// Continue Slave Transmit
//serial_print("t");
if ((status & I2C_S_RXAK) == 0) {
//serial_print(".");
// Master ACK'd previous byte
if (txBufferIndex < txBufferLength) {
port().D = txBuffer[txBufferIndex++];
} else {
port().D = 0;
}
port().C1 = I2C_C1_IICEN | I2C_C1_IICIE | I2C_C1_TX;
} else {
//serial_print("*");
// Master did not ACK previous byte
port().C1 = I2C_C1_IICEN | I2C_C1_IICIE;
data = port().D;
}
} else {
// Continue Slave Receive
irqcount = 0;
#ifdef WIRE_HAS_STOP_INTERRUPT
port().FLT |= I2C_FLT_STOPIE;
#else
#if defined(WIRE_IMPLEMENT_WIRE) && !defined(WIRE_IMPLEMENT_WIRE1)
attachInterrupt(hardware.sda_pin[sda_pin_index], sda_rising_isr0, RISING);
#elif !defined(WIRE_IMPLEMENT_WIRE) && defined(WIRE_IMPLEMENT_WIRE1)
attachInterrupt(hardware.sda_pin[sda_pin_index], sda_rising_isr1, RISING);
#elif defined(WIRE_IMPLEMENT_WIRE) && defined(WIRE_IMPLEMENT_WIRE1)
if (this == &Wire) {
attachInterrupt(hardware.sda_pin[sda_pin_index], sda_rising_isr0, RISING);
} else if (this == &Wire1) {
attachInterrupt(hardware.sda_pin[sda_pin_index], sda_rising_isr1, RISING);
}
#endif
#endif // WIRE_HAS_STOP_INTERRUPT
//digitalWriteFast(4, HIGH);
data = port().D;
//serial_phex(data);
if (rxBufferLength < BUFFER_LENGTH && receiving) {
rxBuffer[rxBufferLength++] = data;
}
//digitalWriteFast(4, LOW);
}
port().S = I2C_S_IICIF;
}
