/* | |
* FreeRTOS Kernel V10.3.0 | |
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*/ | |
/* | |
* This version of comtest. c is for use on systems that have limited stack | |
* space and no display facilities. The complete version can be found in | |
* the Demo/Common/Full directory. | |
* | |
* Creates two tasks that operate on an interrupt driven serial port. A | |
* loopback connector should be used so that everything that is transmitted is | |
* also received. The serial port does not use any flow control. On a | |
* standard 9way 'D' connector pins two and three should be connected together. | |
* | |
* The first task posts a sequence of characters to the Tx queue, toggling an | |
* LED on each successful post. At the end of the sequence it sleeps for a | |
* pseudo-random period before resending the same sequence. | |
* | |
* The UART Tx end interrupt is enabled whenever data is available in the Tx | |
* queue. The Tx end ISR removes a single character from the Tx queue and | |
* passes it to the UART for transmission. | |
* | |
* The second task blocks on the Rx queue waiting for a character to become | |
* available. When the UART Rx end interrupt receives a character it places | |
* it in the Rx queue, waking the second task. The second task checks that the | |
* characters removed from the Rx queue form the same sequence as those posted | |
* to the Tx queue, and toggles an LED for each correct character. | |
* | |
* The receiving task is spawned with a higher priority than the transmitting | |
* task. The receiver will therefore wake every time a character is | |
* transmitted so neither the Tx or Rx queue should ever hold more than a few | |
* characters. | |
* | |
*/ | |
/* Scheduler include files. */ | |
#include <stdlib.h> | |
#include "FreeRTOS.h" | |
#include "task.h" | |
/* Demo program include files. */ | |
#include "serial.h" | |
#include "comtest.h" | |
#include "partest.h" | |
#define comSTACK_SIZE configMINIMAL_STACK_SIZE | |
#define comTX_LED_OFFSET ( 0 ) | |
#define comRX_LED_OFFSET ( 1 ) | |
#define comTOTAL_PERMISSIBLE_ERRORS ( 2 ) | |
/* The Tx task will transmit the sequence of characters at a pseudo random | |
interval. This is the maximum and minimum block time between sends. */ | |
#define comTX_MAX_BLOCK_TIME ( ( TickType_t ) 0x96 ) | |
#define comTX_MIN_BLOCK_TIME ( ( TickType_t ) 0x32 ) | |
#define comOFFSET_TIME ( ( TickType_t ) 3 ) | |
/* We should find that each character can be queued for Tx immediately and we | |
don't have to block to send. */ | |
#define comNO_BLOCK ( ( TickType_t ) 0 ) | |
/* The Rx task will block on the Rx queue for a long period. */ | |
#define comRX_BLOCK_TIME ( ( TickType_t ) 0xffff ) | |
/* The sequence transmitted is from comFIRST_BYTE to and including comLAST_BYTE. */ | |
#define comFIRST_BYTE ( 'A' ) | |
#define comLAST_BYTE ( 'X' ) | |
#define comBUFFER_LEN ( ( UBaseType_t ) ( comLAST_BYTE - comFIRST_BYTE ) + ( UBaseType_t ) 1 ) | |
#define comINITIAL_RX_COUNT_VALUE ( 0 ) | |
/* Handle to the com port used by both tasks. */ | |
static xComPortHandle xPort = NULL; | |
/* The transmit task as described at the top of the file. */ | |
static portTASK_FUNCTION_PROTO( vComTxTask, pvParameters ); | |
/* The receive task as described at the top of the file. */ | |
static portTASK_FUNCTION_PROTO( vComRxTask, pvParameters ); | |
/* The LED that should be toggled by the Rx and Tx tasks. The Rx task will | |
toggle LED ( uxBaseLED + comRX_LED_OFFSET). The Tx task will toggle LED | |
( uxBaseLED + comTX_LED_OFFSET ). */ | |
static UBaseType_t uxBaseLED = 0; | |
/* Check variable used to ensure no error have occurred. The Rx task will | |
increment this variable after every successfully received sequence. If at any | |
time the sequence is incorrect the the variable will stop being incremented. */ | |
static volatile UBaseType_t uxRxLoops = comINITIAL_RX_COUNT_VALUE; | |
/*-----------------------------------------------------------*/ | |
void vAltStartComTestTasks( UBaseType_t uxPriority, uint32_t ulBaudRate, UBaseType_t uxLED ) | |
{ | |
/* Initialise the com port then spawn the Rx and Tx tasks. */ | |
uxBaseLED = uxLED; | |
xSerialPortInitMinimal( ulBaudRate, comBUFFER_LEN ); | |
/* The Tx task is spawned with a lower priority than the Rx task. */ | |
xTaskCreate( vComTxTask, "COMTx", comSTACK_SIZE, NULL, uxPriority - 1, ( TaskHandle_t * ) NULL ); | |
xTaskCreate( vComRxTask, "COMRx", comSTACK_SIZE, NULL, uxPriority, ( TaskHandle_t * ) NULL ); | |
} | |
/*-----------------------------------------------------------*/ | |
static portTASK_FUNCTION( vComTxTask, pvParameters ) | |
{ | |
char cByteToSend; | |
TickType_t xTimeToWait; | |
/* Just to stop compiler warnings. */ | |
( void ) pvParameters; | |
for( ;; ) | |
{ | |
/* Simply transmit a sequence of characters from comFIRST_BYTE to | |
comLAST_BYTE. */ | |
for( cByteToSend = comFIRST_BYTE; cByteToSend <= comLAST_BYTE; cByteToSend++ ) | |
{ | |
if( xSerialPutChar( xPort, cByteToSend, comNO_BLOCK ) == pdPASS ) | |
{ | |
vParTestToggleLED( uxBaseLED + comTX_LED_OFFSET ); | |
} | |
} | |
/* Turn the LED off while we are not doing anything. */ | |
vParTestSetLED( uxBaseLED + comTX_LED_OFFSET, pdFALSE ); | |
/* We have posted all the characters in the string - wait before | |
re-sending. Wait a pseudo-random time as this will provide a better | |
test. */ | |
xTimeToWait = xTaskGetTickCount() + comOFFSET_TIME; | |
/* Make sure we don't wait too long... */ | |
xTimeToWait %= comTX_MAX_BLOCK_TIME; | |
/* ...but we do want to wait. */ | |
if( xTimeToWait < comTX_MIN_BLOCK_TIME ) | |
{ | |
xTimeToWait = comTX_MIN_BLOCK_TIME; | |
} | |
vTaskDelay( xTimeToWait ); | |
} | |
} /*lint !e715 !e818 pvParameters is required for a task function even if it is not referenced. */ | |
/*-----------------------------------------------------------*/ | |
static portTASK_FUNCTION( vComRxTask, pvParameters ) | |
{ | |
signed char cExpectedByte, cByteRxed; | |
BaseType_t xResyncRequired = pdFALSE, xErrorOccurred = pdFALSE; | |
/* Just to stop compiler warnings. */ | |
( void ) pvParameters; | |
for( ;; ) | |
{ | |
/* We expect to receive the characters from comFIRST_BYTE to | |
comLAST_BYTE in an incrementing order. Loop to receive each byte. */ | |
for( cExpectedByte = comFIRST_BYTE; cExpectedByte <= comLAST_BYTE; cExpectedByte++ ) | |
{ | |
/* Block on the queue that contains received bytes until a byte is | |
available. */ | |
if( xSerialGetChar( xPort, &cByteRxed, comRX_BLOCK_TIME ) ) | |
{ | |
/* Was this the byte we were expecting? If so, toggle the LED, | |
otherwise we are out on sync and should break out of the loop | |
until the expected character sequence is about to restart. */ | |
if( cByteRxed == cExpectedByte ) | |
{ | |
vParTestToggleLED( uxBaseLED + comRX_LED_OFFSET ); | |
} | |
else | |
{ | |
xResyncRequired = pdTRUE; | |
break; /*lint !e960 Non-switch break allowed. */ | |
} | |
} | |
} | |
/* Turn the LED off while we are not doing anything. */ | |
vParTestSetLED( uxBaseLED + comRX_LED_OFFSET, pdFALSE ); | |
/* Did we break out of the loop because the characters were received in | |
an unexpected order? If so wait here until the character sequence is | |
about to restart. */ | |
if( xResyncRequired == pdTRUE ) | |
{ | |
while( cByteRxed != comLAST_BYTE ) | |
{ | |
/* Block until the next char is available. */ | |
xSerialGetChar( xPort, &cByteRxed, comRX_BLOCK_TIME ); | |
} | |
/* Note that an error occurred which caused us to have to resync. | |
We use this to stop incrementing the loop counter so | |
sAreComTestTasksStillRunning() will return false - indicating an | |
error. */ | |
xErrorOccurred++; | |
/* We have now resynced with the Tx task and can continue. */ | |
xResyncRequired = pdFALSE; | |
} | |
else | |
{ | |
if( xErrorOccurred < comTOTAL_PERMISSIBLE_ERRORS ) | |
{ | |
/* Increment the count of successful loops. As error | |
occurring (i.e. an unexpected character being received) will | |
prevent this counter being incremented for the rest of the | |
execution. Don't worry about mutual exclusion on this | |
variable - it doesn't really matter as we just want it | |
to change. */ | |
uxRxLoops++; | |
} | |
} | |
} | |
} /*lint !e715 !e818 pvParameters is required for a task function even if it is not referenced. */ | |
/*-----------------------------------------------------------*/ | |
BaseType_t xAreComTestTasksStillRunning( void ) | |
{ | |
BaseType_t xReturn; | |
/* If the count of successful reception loops has not changed than at | |
some time an error occurred (i.e. a character was received out of sequence) | |
and we will return false. */ | |
if( uxRxLoops == comINITIAL_RX_COUNT_VALUE ) | |
{ | |
xReturn = pdFALSE; | |
} | |
else | |
{ | |
xReturn = pdTRUE; | |
} | |
/* Reset the count of successful Rx loops. When this function is called | |
again we expect this to have been incremented. */ | |
uxRxLoops = comINITIAL_RX_COUNT_VALUE; | |
return xReturn; | |
} | |