/* | |
FreeRTOS V6.1.0 - Copyright (C) 2010 Real Time Engineers Ltd. | |
*************************************************************************** | |
* * | |
* If you are: * | |
* * | |
* + New to FreeRTOS, * | |
* + Wanting to learn FreeRTOS or multitasking in general quickly * | |
* + Looking for basic training, * | |
* + Wanting to improve your FreeRTOS skills and productivity * | |
* * | |
* then take a look at the FreeRTOS books - available as PDF or paperback * | |
* * | |
* "Using the FreeRTOS Real Time Kernel - a Practical Guide" * | |
* http://www.FreeRTOS.org/Documentation * | |
* * | |
* A pdf reference manual is also available. Both are usually delivered * | |
* to your inbox within 20 minutes to two hours when purchased between 8am * | |
* and 8pm GMT (although please allow up to 24 hours in case of * | |
* exceptional circumstances). Thank you for your support! * | |
* * | |
*************************************************************************** | |
This file is part of the FreeRTOS distribution. | |
FreeRTOS is free software; you can redistribute it and/or modify it under | |
the terms of the GNU General Public License (version 2) as published by the | |
Free Software Foundation AND MODIFIED BY the FreeRTOS exception. | |
***NOTE*** The exception to the GPL is included to allow you to distribute | |
a combined work that includes FreeRTOS without being obliged to provide the | |
source code for proprietary components outside of the FreeRTOS kernel. | |
FreeRTOS is distributed in the hope that it will be useful, but WITHOUT | |
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
more details. You should have received a copy of the GNU General Public | |
License and the FreeRTOS license exception along with FreeRTOS; if not it | |
can be viewed here: http://www.freertos.org/a00114.html and also obtained | |
by writing to Richard Barry, contact details for whom are available on the | |
FreeRTOS WEB site. | |
1 tab == 4 spaces! | |
http://www.FreeRTOS.org - Documentation, latest information, license and | |
contact details. | |
http://www.SafeRTOS.com - A version that is certified for use in safety | |
critical systems. | |
http://www.OpenRTOS.com - Commercial support, development, porting, | |
licensing and training services. | |
*/ | |
/* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER. | |
* | |
* This file only supports UART 0 | |
*/ | |
/* Standard includes. */ | |
#include <stdlib.h> | |
/* Scheduler includes. */ | |
#include "FreeRTOS.h" | |
#include "queue.h" | |
#include "task.h" | |
/* Demo application includes. */ | |
#include "serial.h" | |
/* The queue used to hold received characters. */ | |
static xQueueHandle xRxedChars; | |
/* The queue used to hold characters waiting transmission. */ | |
static xQueueHandle xCharsForTx; | |
static volatile portSHORT sTHREEmpty; | |
static volatile portSHORT queueFail = pdFALSE; | |
/*-----------------------------------------------------------*/ | |
xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength ) | |
{ | |
/* Initialise the hardware. */ | |
portENTER_CRITICAL(); | |
{ | |
/* Create the queues used by the com test task. */ | |
xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof(signed portCHAR) ); | |
xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof(signed portCHAR) ); | |
if( xRxedChars == 0 ) | |
{ | |
queueFail = pdTRUE; | |
} | |
if( xCharsForTx == 0 ) | |
{ | |
queueFail = pdTRUE; | |
} | |
/* Initialize UART asynchronous mode */ | |
BGR0 = configCLKP1_CLOCK_HZ / ulWantedBaud; | |
SCR0 = 0x17; /* 8N1 */ | |
SMR0 = 0x0d; /* enable SOT3, Reset, normal mode */ | |
SSR0 = 0x02; /* LSB first, enable receive interrupts */ | |
PIER08_IE2 = 1; /* enable input */ | |
DDR08_D2 = 0; /* switch P08_2 to input */ | |
DDR08_D3 = 1; /* switch P08_3 to output */ | |
} | |
portEXIT_CRITICAL(); | |
/* Unlike other ports, this serial code does not allow for more than one | |
com port. We therefore don't return a pointer to a port structure and can | |
instead just return NULL. */ | |
return NULL; | |
} | |
/*-----------------------------------------------------------*/ | |
signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime ) | |
{ | |
/* Get the next character from the buffer. 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 portCHAR cOutChar, portTickType xBlockTime ) | |
{ | |
signed portBASE_TYPE xReturn; | |
/* Transmit a character. */ | |
portENTER_CRITICAL(); | |
{ | |
if( sTHREEmpty == pdTRUE ) | |
{ | |
/* If sTHREEmpty is true then the UART Tx ISR has indicated that | |
there are no characters queued to be transmitted - so we can | |
write the character directly to the shift Tx register. */ | |
sTHREEmpty = pdFALSE; | |
TDR0 = cOutChar; | |
xReturn = pdPASS; | |
} | |
else | |
{ | |
/* sTHREEmpty is false, so there are still characters waiting to be | |
transmitted. We have to queue this character so it gets | |
transmitted in turn. */ | |
/* Return false if after the block time there is no room on the Tx | |
queue. It is ok to block inside a critical section as each task | |
maintains it's own critical section status. */ | |
if( xQueueSend(xCharsForTx, &cOutChar, xBlockTime) == pdTRUE ) | |
{ | |
xReturn = pdPASS; | |
} | |
else | |
{ | |
xReturn = pdFAIL; | |
} | |
} | |
if( pdPASS == xReturn ) | |
{ | |
/* 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. */ | |
SSR0_TIE = 1; | |
} | |
} | |
portEXIT_CRITICAL(); | |
return pdPASS; | |
} | |
/*-----------------------------------------------------------*/ | |
/* | |
* UART RX interrupt service routine. | |
*/ | |
__interrupt void UART0_RxISR( void ) | |
{ | |
volatile signed portCHAR cChar; | |
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE; | |
/* Get the character from the UART and post it on the queue of Rxed | |
characters. */ | |
cChar = RDR0; | |
xQueueSendFromISR( xRxedChars, ( const void *const ) &cChar, &xHigherPriorityTaskWoken ); | |
if( xHigherPriorityTaskWoken ) | |
{ | |
/*If the post causes a task to wake force a context switch | |
as the woken task may have a higher priority than the task we have | |
interrupted. */ | |
portYIELD_FROM_ISR(); | |
} | |
} | |
/*-----------------------------------------------------------*/ | |
/* | |
* UART Tx interrupt service routine. | |
*/ | |
__interrupt void UART0_TxISR( void ) | |
{ | |
signed portCHAR cChar; | |
signed portBASE_TYPE xTaskWoken = pdFALSE; | |
/* The previous character has been transmitted. See if there are any | |
further characters waiting transmission. */ | |
if( xQueueReceiveFromISR(xCharsForTx, &cChar, &xTaskWoken) == pdTRUE ) | |
{ | |
/* There was another character queued - transmit it now. */ | |
TDR0 = cChar; | |
} | |
else | |
{ | |
/* There were no other characters to transmit. */ | |
sTHREEmpty = pdTRUE; | |
/* Disable transmit interrupts */ | |
SSR0_TIE = 0; | |
} | |
} |