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155 lines
5.4 KiB
C
155 lines
5.4 KiB
C
/*
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* FreeRTOS Kernel V10.2.1
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* Copyright (C) 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of
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* this software and associated documentation files (the "Software"), to deal in
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* the Software without restriction, including without limitation the rights to
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* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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* the Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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* http://www.FreeRTOS.org
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* http://aws.amazon.com/freertos
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*
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* 1 tab == 4 spaces!
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*/
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/*
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BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR USART0.
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This file contains all the serial port components that must be compiled
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to ARM mode. The components that can be compiled to either ARM or THUMB
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mode are contained in serial.c.
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*/
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/* Standard includes. */
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#include <stdlib.h>
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/* Scheduler includes. */
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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 includes. */
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#include "serial.h"
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#include "AT91R40008.h"
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#include "usart.h"
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/*-----------------------------------------------------------*/
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/* Constant to access the AIC. */
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#define serCLEAR_AIC_INTERRUPT ( ( unsigned long ) 0 )
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/* Constants to determine the ISR source. */
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#define serSOURCE_THRE ( ( unsigned char ) 0x02 )
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#define serSOURCE_RX_TIMEOUT ( ( unsigned char ) 0x0c )
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#define serSOURCE_ERROR ( ( unsigned char ) 0x06 )
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#define serSOURCE_RX ( ( unsigned char ) 0x04 )
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#define serINTERRUPT_SOURCE_MASK ( ( unsigned long ) (US_RXRDY | US_TXRDY | US_RXBRK | US_OVRE | US_FRAME | US_PARE) )
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/* Queues used to hold received characters, and characters waiting to be
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transmitted. */
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static QueueHandle_t xRxedChars;
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static QueueHandle_t xCharsForTx;
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/*-----------------------------------------------------------*/
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/* UART0 interrupt service routine. This can cause a context switch so MUST
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be declared "naked". */
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void vUART_ISR_Wrapper( void ) __attribute__ ((naked));
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/* The ISR function that actually performs the work. This must be separate
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from the wrapper to ensure the correct stack frame is set up. */
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void vUART_ISR_Handler( void ) __attribute__ ((noinline));
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/*-----------------------------------------------------------*/
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void vSerialISRCreateQueues( unsigned portBASE_TYPE uxQueueLength, QueueHandle_t *pxRxedChars, QueueHandle_t *pxCharsForTx )
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{
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/* Create the queues used to hold Rx and Tx characters. */
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xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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/* Pass back a reference to the queues so the serial API file can
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post/receive characters. */
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*pxRxedChars = xRxedChars;
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*pxCharsForTx = xCharsForTx;
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}
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/*-----------------------------------------------------------*/
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void vUART_ISR_Wrapper( void )
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{
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/* Save the context of the interrupted task. */
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portSAVE_CONTEXT();
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/* Call the handler. This must be a separate function to ensure the
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stack frame is correctly set up. */
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__asm volatile( "bl vUART_ISR_Handler" );
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/* Restore the context of whichever task will run next. */
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portRESTORE_CONTEXT();
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}
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/*-----------------------------------------------------------*/
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void vUART_ISR_Handler( void )
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{
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/* Now we can declare the local variables. These must be static. */
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signed char cChar;
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portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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unsigned long ulStatus;
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/* What caused the interrupt? */
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ulStatus = AT91C_BASE_US0->US_CSR & AT91C_BASE_US0->US_IMR;
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if (ulStatus & US_TXRDY)
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{
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/* The interrupt was caused by the THR becoming empty. Are there any
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more characters to transmit? */
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if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
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{
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/* A character was retrieved from the queue so can be sent to the
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THR now. */
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AT91C_BASE_US0->US_THR = cChar;
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}
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else
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{
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/* Queue empty, nothing to send so turn off the Tx interrupt. */
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AT91C_BASE_US0->US_IDR = US_TXRDY;
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}
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}
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if (ulStatus & US_RXRDY)
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{
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/* The interrupt was caused by the receiver getting data. */
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cChar = AT91C_BASE_US0->US_RHR;
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xQueueSendFromISR(xRxedChars, &cChar, &xHigherPriorityTaskWoken);
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}
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/* Acknowledge the interrupt at AIC level... */
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AT91C_BASE_AIC->AIC_EOICR = serCLEAR_AIC_INTERRUPT;
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/* If an event caused a task to unblock then we call "Yield from ISR" to
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ensure that the unblocked task is the task that executes when the interrupt
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completes if the unblocked task has a priority higher than the interrupted
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task. */
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if( xHigherPriorityTaskWoken )
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{
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portYIELD_FROM_ISR();
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}
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}
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/*-----------------------------------------------------------*/
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