/**
* Send the given byte to the USART. It is added to the transmit buffer, and asynchronously
* transmitted.
*
* @param c Byte to write out on the serial port
*/
void serPutByte(BYTE c) {
//Check if buffer is full.
#ifdef SER_WAIT_FOR_TXBUF
//Wait until a byte is transmitted by the interrupt routine and buffer has place again.
while (busIsTxBufFull(BUSID)) {
FAST_USER_PROCESS();
}
#else
if (busIsTxBufFull(BUSID)) {
serStat |= SER1_TXBUF_OVERRUN;
return;
}
#endif
//Enter critical section
DISBALE_INTERRUPTS();
//If we are not currently TXing, the TX buffer will be empty. No need to transmit via buffer,
//just write direct to TXREG
if ( !PIE1_TXIE)
{
TXREG = c; //Send byte
PIE1_TXIE = 1; //Indicate that we are currently TXing
ENABLE_INTERRUPTS();
}
//We are currently TXing. This means that the TXIF will soon be set after the current byte
//has been transmitted, and the TX buffer will be checked for any unsent data. Add current
//byte to TX buffer.
else {
//Add byte to TX buffer, and update buffer pointers
busPutByteTxBuf(BUFID, c);
ENABLE_INTERRUPTS();
}
}
void serPutByte( BYTE c )
{
#ifdef SER_WAIT_FOR_TXBUF
// Check if buffer is full. If this is the case, wait until a byte is transmitted by the
// interrupt routine and buffer has place again.
while ( ( ( idxSerTxbufPut + 1 ) & SER_TXBUF_MASK ) == idxSerTxbufGet ) {
CLRWDT();
}
#endif
// Enter critical section
DISBALE_INTERRUPTS();
// If we are not currently transmitting, the TX buffer will be empty.
// No need to transmit via buffer,
// just write direct to TXREG
if ( !PIE1_TXIE ) {
TXREG = c; // Send byte
PIE1_TXIE = 1; // Indicate that we are currently TXing
ENABLE_INTERRUPTS();
}
// We are currently trsanmitting. This means that the TXIF will soon be set after the current byte
// has been transmitted, and the TX buffer will be checked for any unsent data. Add current
// byte to TX buffer.
else {
// Seeing that an TX interrupt can happen any time during this function, only update idxTxbufPut
// at the end of the routine
txBuf[ idxSerTxbufPut ] = c;
idxSerTxbufPut = ( ++idxSerTxbufPut ) & SER_TXBUF_MASK;
ENABLE_INTERRUPTS();
}
}
