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/*
* FreeRTOS Kernel V10.3.0
* Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* http://www.FreeRTOS.org
* http://aws.amazon.com/freertos
*
* 1 tab == 4 spaces!
*/
/* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER for port 1.
Note that this driver is written to test the RTOS port and is not intended
to represent an optimised solution. */
/* Processor Expert generated includes. */
#include "com0.h"
/* Scheduler include files. */
#include "FreeRTOS.h"
#include "queue.h"
#include "task.h"
/* Demo application include files. */
#include "serial.h"
/* The queues used to communicate between the task code and the interrupt
service routines. */
static QueueHandle_t xRxedChars;
static QueueHandle_t xCharsForTx;
/* Interrupt identification bits. */
#define serOVERRUN_INTERRUPT ( 0x08 )
#define serRX_INTERRUPT ( 0x20 )
#define serTX_INTERRUPT ( 0x80 )
/*-----------------------------------------------------------*/
/*
* Initialise port for interrupt driven communications.
*/
xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
{
/* Hardware setup is performed by the Processor Expert generated code.
This function just creates the queues used to communicate between the
interrupt code and the task code - then sets the required baud rate. */
xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
COM0_SetBaudRateMode( ( char ) ulWantedBaud );
return NULL;
}
/*-----------------------------------------------------------*/
signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, TickType_t xBlockTime )
{
/* Get the next character from the buffer queue. Return false if no characters
are available, or arrive before xBlockTime expires. */
if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
{
return pdTRUE;
}
else
{
return pdFALSE;
}
}
/*-----------------------------------------------------------*/
signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, TickType_t xBlockTime )
{
/* Place the character in the queue of characters to be transmitted. */
if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
{
return pdFAIL;
}
/* Turn on the Tx interrupt so the ISR will remove the character from the
queue and send it. This does not need to be in a critical section as
if the interrupt has already removed the character the next interrupt
will simply turn off the Tx interrupt again. */
SCI0CR2_SCTIE = 1;;
return pdPASS;
}
/*-----------------------------------------------------------*/
void vSerialClose( xComPortHandle xPort )
{
/* Not supported. */
( void ) xPort;
}
/*-----------------------------------------------------------*/
/*
* Interrupt service routine for the serial port. Must be in non-banked
* memory.
*/
#pragma CODE_SEG __NEAR_SEG NON_BANKED
__interrupt void vCOM0_ISR( void )
{
volatile unsigned char ucByte, ucStatus;
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
/* What caused the interrupt? */
ucStatus = SCI0SR1;
if( ucStatus & serOVERRUN_INTERRUPT )
{
/* The interrupt was caused by an overrun. Clear the error by reading
the data register. */
ucByte = SCI0DRL;
}
if( ucStatus & serRX_INTERRUPT )
{
/* The interrupt was caused by a character being received.
Read the received byte. */
ucByte = SCI0DRL;
/* Post the character onto the queue of received characters - noting
whether or not this wakes a task. */
xQueueSendFromISR( xRxedChars, ( void * ) &ucByte, &xHigherPriorityTaskWoken );
}
if( ( ucStatus & serTX_INTERRUPT ) && ( SCI0CR2_SCTIE ) )
{
/* The interrupt was caused by a character being transmitted. */
if( xQueueReceiveFromISR( xCharsForTx, ( void * ) &ucByte, &xHigherPriorityTaskWoken ) == pdTRUE )
{
/* Clear the SCRF bit. */
SCI0DRL = ucByte;
}
else
{
/* Disable transmit interrupt */
SCI0CR2_SCTIE = 0;
}
}
if( xHigherPriorityTaskWoken )
{
portYIELD();
}
}
#pragma CODE_SEG DEFAULT
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