/* | |
FreeRTOS V8.2.2 - Copyright (C) 2015 Real Time Engineers Ltd. | |
All rights reserved | |
VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION. | |
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 modification 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. Full license text is available on the following | |
link: http://www.freertos.org/a00114.html | |
*************************************************************************** | |
* * | |
* FreeRTOS provides completely free yet professionally developed, * | |
* robust, strictly quality controlled, supported, and cross * | |
* platform software that is more than just the market leader, it * | |
* is the industry's de facto standard. * | |
* * | |
* Help yourself get started quickly while simultaneously helping * | |
* to support the FreeRTOS project by purchasing a FreeRTOS * | |
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* http://www.FreeRTOS.org/Documentation * | |
* * | |
*************************************************************************** | |
http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading | |
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defined configASSERT()? | |
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mission critical applications that require provable dependability. | |
1 tab == 4 spaces! | |
*/ | |
/* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR IAR AVR PORT. */ | |
#include <stdlib.h> | |
#include "FreeRTOS.h" | |
#include "queue.h" | |
#include "task.h" | |
#include "serial.h" | |
#define serBAUD_DIV_CONSTANT ( ( unsigned long ) 16 ) | |
/* Constants for writing to UCSRB. */ | |
#define serRX_INT_ENABLE ( ( unsigned char ) 0x80 ) | |
#define serRX_ENABLE ( ( unsigned char ) 0x10 ) | |
#define serTX_ENABLE ( ( unsigned char ) 0x08 ) | |
#define serTX_INT_ENABLE ( ( unsigned char ) 0x20 ) | |
/* Constants for writing to UCSRC. */ | |
#define serUCSRC_SELECT ( ( unsigned char ) 0x80 ) | |
#define serEIGHT_DATA_BITS ( ( unsigned char ) 0x06 ) | |
static QueueHandle_t xRxedChars; | |
static QueueHandle_t xCharsForTx; | |
#define vInterruptOn() \ | |
{ \ | |
unsigned char ucByte; \ | |
\ | |
ucByte = UCSRB; \ | |
ucByte |= serTX_INT_ENABLE; \ | |
outb( UCSRB, ucByte ); \ | |
} | |
/*-----------------------------------------------------------*/ | |
#define vInterruptOff() \ | |
{ \ | |
unsigned char ucByte; \ | |
\ | |
ucByte = UCSRB; \ | |
ucByte &= ~serTX_INT_ENABLE; \ | |
outb( UCSRB, ucByte ); \ | |
} | |
/*-----------------------------------------------------------*/ | |
xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength ) | |
{ | |
unsigned long ulBaudRateCounter; | |
unsigned char ucByte; | |
portENTER_CRITICAL(); | |
{ | |
/* Create the queues used by the com test task. */ | |
xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) ); | |
xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) ); | |
/* Calculate the baud rate register value from the equation in the | |
data sheet. */ | |
ulBaudRateCounter = ( configCPU_CLOCK_HZ / ( serBAUD_DIV_CONSTANT * ulWantedBaud ) ) - ( unsigned long ) 1; | |
/* Set the baud rate. */ | |
ucByte = ( unsigned char ) ( ulBaudRateCounter & ( unsigned long ) 0xff ); | |
outb( UBRRL, ucByte ); | |
ulBaudRateCounter >>= ( unsigned long ) 8; | |
ucByte = ( unsigned char ) ( ulBaudRateCounter & ( unsigned long ) 0xff ); | |
outb( UBRRH, ucByte ); | |
/* Enable the Rx interrupt. The Tx interrupt will get enabled | |
later. Also enable the Rx and Tx. */ | |
outb( UCSRB, serRX_INT_ENABLE | serRX_ENABLE | serTX_ENABLE ); | |
/* Set the data bits to 8. */ | |
outb( UCSRC, serUCSRC_SELECT | serEIGHT_DATA_BITS ); | |
} | |
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 char *pcRxedChar, TickType_t 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 char cOutChar, TickType_t xBlockTime ) | |
{ | |
/* Return false if after the block time there is no room on the Tx queue. */ | |
if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS ) | |
{ | |
return pdFAIL; | |
} | |
vInterruptOn(); | |
return pdPASS; | |
} | |
/*-----------------------------------------------------------*/ | |
void vSerialClose( xComPortHandle xPort ) | |
{ | |
unsigned char ucByte; | |
/* Turn off the interrupts. We may also want to delete the queues and/or | |
re-install the original ISR. */ | |
portENTER_CRITICAL(); | |
{ | |
vInterruptOff(); | |
ucByte = UCSRB; | |
ucByte &= ~serRX_INT_ENABLE; | |
outb( UCSRB, ucByte ); | |
} | |
portEXIT_CRITICAL(); | |
} | |
/*-----------------------------------------------------------*/ | |
__interrupt void SIG_UART_RECV( void ) | |
{ | |
signed char ucChar, xHigherPriorityTaskWoken = pdFALSE; | |
/* Get the character and post it on the queue of Rxed characters. | |
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. */ | |
ucChar = UDR; | |
xQueueSendFromISR( xRxedChars, &ucChar, &xHigherPriorityTaskWoken ); | |
if( xHigherPriorityTaskWoken != pdFALSE ) | |
{ | |
taskYIELD(); | |
} | |
} | |
/*-----------------------------------------------------------*/ | |
__interrupt void SIG_UART_DATA( void ) | |
{ | |
signed char cChar, cTaskWoken = pdFALSE; | |
if( xQueueReceiveFromISR( xCharsForTx, &cChar, &cTaskWoken ) == pdTRUE ) | |
{ | |
/* Send the next character queued for Tx. */ | |
outb( UDR, cChar ); | |
} | |
else | |
{ | |
/* Queue empty, nothing to send. */ | |
vInterruptOff(); | |
} | |
} | |