/*************************************************************************//*!
* \brief Drops a character into the transmit ring buffer.
*
* If the ring buffer is full, the function delays to allow transmission of characters to free
* up space in buffer. The function turns on the transmit interrupt for the USART.
* @param usartId
* @param cOutChar
* @return
*/
UBaseType_t usart_xputChar(USART_ID usartId, const UBaseType_t cOutChar )
{
// Return false if there remains no room on the Tx ring buffer
UBaseType_t retVal = pdPASS;
if( ! ringBuffer_IsFull( &(usartComBuf[usartId].xCharsForTx) ) )
ringBuffer_Poke( &(usartComBuf[usartId].xCharsForTx), cOutChar ); // poke in a fast byte
else
{
// go slower, per character rate for 115200 is 86us
_delay_us(25); // delay for about one character (maximum _delay_loop_1() delay is 32 us at 22MHz)
_delay_us(25);
_delay_us(25);
_delay_us(25);
if( ! ringBuffer_IsFull( &(usartComBuf[usartId].xCharsForTx) ) )
ringBuffer_Poke( &(usartComBuf[usartId].xCharsForTx), cOutChar ); // poke in a byte slowly
else
retVal = pdFAIL; // if the Tx ring buffer remains full
}
xmitInterrupt_On(usartId);
return retVal;
}
inline portBASE_TYPE xSerialPutChar( xComPortHandlePtr pxPort, unsigned const portBASE_TYPE cOutChar )
{
/* Return false if there remains no room on the Tx ring buffer */
if( ! ringBuffer_IsFull( &(pxPort->xCharsForTx) ) )
ringBuffer_Poke( &(pxPort->xCharsForTx), cOutChar ); // poke in a fast byte
else
{
// go slower, per character rate for 115200 is 86us
_delay_us(25); // delay for about one character (maximum _delay_loop_1() delay is 32 us at 22MHz)
_delay_us(25);
_delay_us(25);
_delay_us(25);
if( ! ringBuffer_IsFull( &(pxPort->xCharsForTx) ) )
ringBuffer_Poke( &(pxPort->xCharsForTx), cOutChar ); // poke in a byte slowly
else
return pdFAIL; // if the Tx ring buffer remains full
}
switch (pxPort->usart)
{
case USART0:
vInterrupt0_On();
break;
case USART1:
vInterrupt1_On();
break;
case USART2:
case USART3:
default:
break;
}
return pdPASS;
}
/*************************************************************************************//*!
* \private Interrupt service routine for character reception.
* Saves a received character in the receive ring buffer. If an error occurred, nothing is done.
* If the ring buffer is full, the character is lost.
* @param usartId - USART id
******************************************************************************************/
void usart_rx_isr(USART_ID usartId)
{
uint8_t cChar;
/* Get status and data from buffer */
/* If error bit set (Frame Error, Data Over Run, Parity), do nothing */
if ( ! (*usartReg[usartId].ucsrAPtr & ((1<<FE0)|(1<<DOR0)|(1<<UPE0)) ) )
{
/* If no error, get the character and post it on the buffer of Rxed characters.*/
cChar = *usartReg[usartId].udrPtr;
if( ! ringBuffer_IsFull( &(usartComBuf[usartId].xRxedChars) ) )
ringBuffer_Poke( &(usartComBuf[usartId].xRxedChars), cChar);
}
}