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jeremybenn |
/*
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serial.c for using FreeRTOS
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Copyright (C) 2005 Robotronics Inc.
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*/
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/* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER for port 1.
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GCC demo modifications by Jeff Smith, Robotronics Inc. 2005
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*/
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#include "cpu.h"
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#include <sys/sio.h>
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/* Scheduler include files. */
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#include "FreeRTOS.h"
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#include "queue.h"
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#include "task.h"
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/* Demo application include files. */
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#include "sci.h"
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#include "serial.h"
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/* The queues used to communicate between the task code and the interrupt
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service routines. */
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static xQueueHandle xRxedChars;
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static xQueueHandle xCharsForTx;
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/* Interrupt identification bits. */
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#define serOVERRUN_INTERRUPT ( '\x08' )
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#define serRX_INTERRUPT ( 0x20 )
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#define serTX_INTERRUPT ( 0x80 )
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/*-----------------------------------------------------------*/
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/*
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* Initialise port for interrupt driven communications.
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*/
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xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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{
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/* Hardware setup is performed by the Processor Expert generated code.
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This function just creates the queues used to communicate between the
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interrupt code and the task code - then sets the required baud rate. */
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xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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SCI_SetBaudRateMode( ( char ) ulWantedBaud );
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return NULL;
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}
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/*-----------------------------------------------------------*/
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signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
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{
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/* Get the next character from the buffer queue. Return false if no characters
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are available, or arrive before xBlockTime expires. */
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if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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{
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return pdTRUE;
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}
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else
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{
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return pdFALSE;
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}
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}
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/*-----------------------------------------------------------*/
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signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
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{
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/* Place the character in the queue of characters to be transmitted. */
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if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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{
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return pdFAIL;
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}
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/* Turn on the Tx interrupt so the ISR will remove the character from the
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queue and send it. This does not need to be in a critical section as
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if the interrupt has already removed the character the next interrupt
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will simply turn off the Tx interrupt again. */
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SCICR2 |= 0x80; // TIE
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return pdPASS;
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}
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/*-----------------------------------------------------------*/
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void vSerialClose( xComPortHandle xPort )
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{
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/* Not supported. */
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//( void ) xPort;
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}
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/*-----------------------------------------------------------*/
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/*
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* Interrupt service routine for the serial port. Must be in non-banked
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* memory.
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*/
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void ATTR_INT ATTR_NEAR vCOM_ISR( void );
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void vCOM_ISR( void )
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{
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volatile unsigned char ucByte, ucStatus;
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portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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/* What caused the interrupt? */
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ucStatus = SCISR1;
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if( ucStatus & serOVERRUN_INTERRUPT )
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{
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/* The interrupt was caused by an overrun. Clear the error by reading
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the data register. */
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ucByte = SCIDRL;
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}
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else
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if( ucStatus & serRX_INTERRUPT )
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{
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/* The interrupt was caused by a character being received.
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Read the received byte. */
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ucByte = SCIDRL;
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/* Post the character onto the queue of received characters - noting
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whether or not this wakes a task. */
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xQueueSendFromISR( xRxedChars, ( void * ) &ucByte, &xHigherPriorityTaskWoken );
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}
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if( ( ucStatus & serTX_INTERRUPT ) && ( SCICR2 & 0x80 ) )
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{
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/* The interrupt was caused by a character being transmitted. */
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if( xQueueReceiveFromISR( xCharsForTx, ( void * ) &ucByte, &xHigherPriorityTaskWoken ) == pdTRUE )
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{
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/* Clear the SCRF bit. */
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SCIDRL = ucByte;
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}
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else
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{
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/* Disable transmit interrupt */
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SCICR2 &= ~0x80; // TIE
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}
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}
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if( xHigherPriorityTaskWoken )
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{
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portYIELD();
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}
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}
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