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jeremybenn |
/*
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FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd.
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***************************************************************************
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* *
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* If you are: *
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* *
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* + New to FreeRTOS, *
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* + Wanting to learn FreeRTOS or multitasking in general quickly *
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* + Looking for basic training, *
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* + Wanting to improve your FreeRTOS skills and productivity *
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* *
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* then take a look at the FreeRTOS books - available as PDF or paperback *
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* *
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* "Using the FreeRTOS Real Time Kernel - a Practical Guide" *
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* http://www.FreeRTOS.org/Documentation *
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* *
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* A pdf reference manual is also available. Both are usually delivered *
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* to your inbox within 20 minutes to two hours when purchased between 8am *
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* and 8pm GMT (although please allow up to 24 hours in case of *
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* exceptional circumstances). Thank you for your support! *
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* *
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***************************************************************************
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This file is part of the FreeRTOS distribution.
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FreeRTOS is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License (version 2) as published by the
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Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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***NOTE*** The exception to the GPL is included to allow you to distribute
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a combined work that includes FreeRTOS without being obliged to provide the
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source code for proprietary components outside of the FreeRTOS kernel.
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FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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more details. You should have received a copy of the GNU General Public
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License and the FreeRTOS license exception along with FreeRTOS; if not it
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can be viewed here: http://www.freertos.org/a00114.html and also obtained
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by writing to Richard Barry, contact details for whom are available on the
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FreeRTOS WEB site.
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1 tab == 4 spaces!
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http://www.FreeRTOS.org - Documentation, latest information, license and
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contact details.
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http://www.SafeRTOS.com - A version that is certified for use in safety
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critical systems.
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http://www.OpenRTOS.com - Commercial support, development, porting,
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licensing and training services.
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*/
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/*
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* The comms test Rx and Tx task and co-routine. See the comments at the top
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* of main.c for full information.
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*/
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/* Scheduler include files. */
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#include "FreeRTOS.h"
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#include "task.h"
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#include "queue.h"
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#include "croutine.h"
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/* Demo application include files. */
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#include "partest.h"
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/* Library include files. */
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#include "DriverLib.h"
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/* The LED's toggled by the various tasks. */
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#define commsFAIL_LED ( 7 )
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#define commsRX_LED ( 6 )
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#define commsTX_LED ( 5 )
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/* The length of the queue used to pass received characters to the Comms Rx
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task. */
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#define commsRX_QUEUE_LEN ( 5 )
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/* The baud rate used by the UART comms tasks/co-routine. */
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#define commsBAUD_RATE ( 57600 )
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/* FIFO setting for the UART. The FIFO is not used to create a better test. */
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#define commsFIFO_SET ( 0x10 )
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/* The string that is transmitted on the UART contains sequentially the
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characters from commsFIRST_TX_CHAR to commsLAST_TX_CHAR. */
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#define commsFIRST_TX_CHAR '0'
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#define commsLAST_TX_CHAR 'z'
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/* Just used to walk through the program memory in order that some random data
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can be generated. */
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#define commsTOTAL_PROGRAM_MEMORY ( ( unsigned long * ) ( 8 * 1024 ) )
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#define commsFIRST_PROGRAM_BYTES ( ( unsigned long * ) 4 )
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/* The time between transmissions of the string on UART 0. This is pseudo
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random in order to generate a bit or randomness to when the interrupts occur.*/
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#define commsMIN_TX_DELAY ( 40 / portTICK_RATE_MS )
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#define commsMAX_TX_DELAY ( ( portTickType ) 0x7f )
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#define commsOFFSET_TIME ( ( portTickType ) 3 )
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/* The time the Comms Rx task should wait to receive a character. This should
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be slightly longer than the time between transmissions. If we do not receive
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a character after this time then there must be an error in the transmission or
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the timing of the transmission. */
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#define commsRX_DELAY ( commsMAX_TX_DELAY + 20 )
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static unsigned portBASE_TYPE uxCommsErrorStatus = pdPASS;
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/* The queue used to pass characters out of the ISR. */
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static xQueueHandle xCommsQueue;
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/* The next character to transmit. */
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static char cNextChar;
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/*-----------------------------------------------------------*/
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void vSerialInit( void )
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{
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/* Create the queue used to communicate between the UART ISR and the Comms
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Rx task. */
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xCommsQueue = xQueueCreate( commsRX_QUEUE_LEN, sizeof( char ) );
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/* Enable the UART. GPIOA has already been initialised. */
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SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
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/* Set GPIO A0 and A1 as peripheral function. They are used to output the
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UART signals. */
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GPIODirModeSet( GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1, GPIO_DIR_MODE_HW );
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/* Configure the UART for 8-N-1 operation. */
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UARTConfigSetExpClk( UART0_BASE, SysCtlClockGet(), commsBAUD_RATE, UART_CONFIG_WLEN_8 | UART_CONFIG_PAR_NONE | UART_CONFIG_STOP_ONE );
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/* We dont want to use the fifo. This is for test purposes to generate
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as many interrupts as possible. */
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HWREG( UART0_BASE + UART_O_LCR_H ) &= ~commsFIFO_SET;
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/* Enable both Rx and Tx interrupts. */
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HWREG( UART0_BASE + UART_O_IM ) |= ( UART_INT_TX | UART_INT_RX );
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IntPrioritySet( INT_UART0, configKERNEL_INTERRUPT_PRIORITY );
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IntEnable( INT_UART0 );
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}
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/*-----------------------------------------------------------*/
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void vSerialTxCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
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{
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portTickType xDelayPeriod;
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static unsigned long *pulRandomBytes = commsFIRST_PROGRAM_BYTES;
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/* Co-routine MUST start with a call to crSTART. */
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crSTART( xHandle );
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for(;;)
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{
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/* Was the previously transmitted string received correctly? */
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if( uxCommsErrorStatus != pdPASS )
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{
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/* An error was encountered so set the error LED. */
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vParTestSetLED( commsFAIL_LED, pdTRUE );
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}
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/* The next character to Tx is the first in the string. */
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cNextChar = commsFIRST_TX_CHAR;
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UARTIntDisable( UART0_BASE, UART_INT_TX );
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{
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/* Send the first character. */
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if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
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{
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HWREG( UART0_BASE + UART_O_DR ) = cNextChar;
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}
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/* Move the variable to the char to Tx on so the ISR transmits
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the next character in the string once this one has completed. */
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cNextChar++;
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}
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UARTIntEnable(UART0_BASE, UART_INT_TX);
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/* Toggle the LED to show a new string is being transmitted. */
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vParTestToggleLED( commsTX_LED );
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/* Delay before we start the string off again. A pseudo-random delay
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is used as this will provide a better test. */
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xDelayPeriod = xTaskGetTickCount() + ( *pulRandomBytes );
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pulRandomBytes++;
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if( pulRandomBytes > commsTOTAL_PROGRAM_MEMORY )
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{
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pulRandomBytes = commsFIRST_PROGRAM_BYTES;
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}
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/* Make sure we don't wait too long... */
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xDelayPeriod &= commsMAX_TX_DELAY;
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/* ...but we do want to wait. */
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if( xDelayPeriod < commsMIN_TX_DELAY )
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{
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xDelayPeriod = commsMIN_TX_DELAY;
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}
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/* Block for the random(ish) time. */
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crDELAY( xHandle, xDelayPeriod );
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}
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/* Co-routine MUST end with a call to crEND. */
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crEND();
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}
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/*-----------------------------------------------------------*/
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void vUART_ISR( void )
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{
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unsigned long ulStatus;
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char cRxedChar;
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portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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/* What caused the interrupt. */
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ulStatus = UARTIntStatus( UART0_BASE, pdTRUE );
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/* Clear the interrupt. */
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UARTIntClear( UART0_BASE, ulStatus );
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/* Was an Rx interrpt pending? */
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if( ulStatus & UART_INT_RX )
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{
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if( ( HWREG(UART0_BASE + UART_O_FR ) & UART_FR_RXFF ) )
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{
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/* Get the char from the buffer and post it onto the queue of
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Rxed chars. Posting the character should wake the task that is
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blocked on the queue waiting for characters. */
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cRxedChar = ( char ) HWREG( UART0_BASE + UART_O_DR );
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xQueueSendFromISR( xCommsQueue, &cRxedChar, &xHigherPriorityTaskWoken );
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}
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}
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/* Was a Tx interrupt pending? */
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if( ulStatus & UART_INT_TX )
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{
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/* Send the next character in the string. We are not using the FIFO. */
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if( cNextChar <= commsLAST_TX_CHAR )
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{
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if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
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{
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HWREG( UART0_BASE + UART_O_DR ) = cNextChar;
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}
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cNextChar++;
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}
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}
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/* If a task was woken by the character being received then we force
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a context switch to occur in case the task is of higher priority than
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the currently executing task (i.e. the task that this interrupt
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interrupted.) */
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portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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}
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/*-----------------------------------------------------------*/
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void vCommsRxTask( void * pvParameters )
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{
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static char cRxedChar, cExpectedChar;
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/* Set the char we expect to receive to the start of the string. */
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cExpectedChar = commsFIRST_TX_CHAR;
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for( ;; )
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{
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/* Wait for a character to be received. */
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xQueueReceive( xCommsQueue, ( void * ) &cRxedChar, commsRX_DELAY );
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/* Was the character recived (if any) the expected character. */
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if( cRxedChar != cExpectedChar )
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{
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/* Got an unexpected character. This can sometimes occur when
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reseting the system using the debugger leaving characters already
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in the UART regsters. */
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uxCommsErrorStatus = pdFAIL;
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/* Resync by waiting for the end of the current string. */
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while( cRxedChar != commsLAST_TX_CHAR )
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{
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while( !xQueueReceive( xCommsQueue, ( void * ) &cRxedChar, portMAX_DELAY ) );
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}
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/* The next expected character is the start of the string again. */
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cExpectedChar = commsFIRST_TX_CHAR;
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}
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else
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{
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if( cExpectedChar == commsLAST_TX_CHAR )
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{
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/* We have reached the end of the string - we now expect to
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receive the first character in the string again. The LED is
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toggled to indicate that the entire string was received without
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error. */
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vParTestToggleLED( commsRX_LED );
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cExpectedChar = commsFIRST_TX_CHAR;
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}
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else
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{
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/* We got the expected character, we now expect to receive the
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next character in the string. */
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cExpectedChar++;
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}
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}
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}
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}
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/*-----------------------------------------------------------*/
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unsigned portBASE_TYPE uxGetCommsStatus( void )
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{
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return uxCommsErrorStatus;
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}
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