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/*
* FreeRTOS Kernel V10.4.1
* Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* http://www.FreeRTOS.org
* http://aws.amazon.com/freertos
*
* 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();
}
}
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