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/*
* FreeRTOS Kernel V10.4.0
* 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 DEMO PURPOSES */
#include <stdlib.h>
#include "FreeRTOS.h"
#include "queue.h"
#include "task.h"
#include "serial.h"
/* Constants required to setup the serial control register. */
#define ser8_BIT_MODE ( ( unsigned char ) 0x40 )
#define serRX_ENABLE ( ( unsigned char ) 0x10 )
/* Constants to setup the timer used to generate the baud rate. */
#define serCLOCK_DIV_48 ( ( unsigned char ) 0x03 )
#define serUSE_PRESCALED_CLOCK ( ( unsigned char ) 0x10 )
#define ser8BIT_WITH_RELOAD ( ( unsigned char ) 0x20 )
#define serSMOD ( ( unsigned char ) 0x10 )
static QueueHandle_t xRxedChars;
static QueueHandle_t xCharsForTx;
data static unsigned portBASE_TYPE uxTxEmpty;
/*-----------------------------------------------------------*/
xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
{
unsigned long ulReloadValue;
const portFLOAT fBaudConst = ( portFLOAT ) configCPU_CLOCK_HZ * ( portFLOAT ) 2.0;
unsigned char ucOriginalSFRPage;
portENTER_CRITICAL();
{
ucOriginalSFRPage = SFRPAGE;
SFRPAGE = 0;
uxTxEmpty = pdTRUE;
/* Create the queues used by the com test task. */
xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( char ) );
xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( char ) );
/* Calculate the baud rate to use timer 1. */
ulReloadValue = ( unsigned long ) ( ( ( portFLOAT ) 256 - ( fBaudConst / ( portFLOAT ) ( 32 * ulWantedBaud ) ) ) + ( portFLOAT ) 0.5 );
/* Set timer one for desired mode of operation. */
TMOD &= 0x08;
TMOD |= ser8BIT_WITH_RELOAD;
SSTA0 |= serSMOD;
/* Set the reload and start values for the time. */
TL1 = ( unsigned char ) ulReloadValue;
TH1 = ( unsigned char ) ulReloadValue;
/* Setup the control register for standard n, 8, 1 - variable baud rate. */
SCON = ser8_BIT_MODE | serRX_ENABLE;
/* Enable the serial port interrupts */
ES = 1;
/* Start the timer. */
TR1 = 1;
SFRPAGE = ucOriginalSFRPage;
}
portEXIT_CRITICAL();
/* Unlike some 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;
}
/*-----------------------------------------------------------*/
void vSerialISR( void ) interrupt 4
{
char cChar;
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
/* 8051 port interrupt routines MUST be placed within a critical section
if taskYIELD() is used within the ISR! */
portENTER_CRITICAL();
{
if( RI )
{
/* Get the character and post it on the queue of Rxed characters.
If the post causes a task to wake force a context switch if the woken task
has a higher priority than the task we have interrupted. */
cChar = SBUF;
RI = 0;
xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
}
if( TI )
{
if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == ( portBASE_TYPE ) pdTRUE )
{
/* Send the next character queued for Tx. */
SBUF = cChar;
}
else
{
/* Queue empty, nothing to send. */
uxTxEmpty = pdTRUE;
}
TI = 0;
}
if( xHigherPriorityTaskWoken )
{
portYIELD();
}
}
portEXIT_CRITICAL();
}
/*-----------------------------------------------------------*/
portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, TickType_t xBlockTime )
{
/* There is only one port supported. */
( void ) pxPort;
/* 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 ( portBASE_TYPE ) pdTRUE;
}
else
{
return ( portBASE_TYPE ) pdFALSE;
}
}
/*-----------------------------------------------------------*/
portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, TickType_t xBlockTime )
{
portBASE_TYPE xReturn;
/* There is only one port supported. */
( void ) pxPort;
portENTER_CRITICAL();
{
if( uxTxEmpty == pdTRUE )
{
SBUF = cOutChar;
uxTxEmpty = pdFALSE;
xReturn = ( portBASE_TYPE ) pdTRUE;
}
else
{
xReturn = xQueueSend( xCharsForTx, &cOutChar, xBlockTime );
if( xReturn == ( portBASE_TYPE ) pdFALSE )
{
xReturn = ( portBASE_TYPE ) pdTRUE;
}
}
}
portEXIT_CRITICAL();
return xReturn;
}
/*-----------------------------------------------------------*/
void vSerialClose( xComPortHandle xPort )
{
/* Not implemented in this port. */
( void ) xPort;
}
/*-----------------------------------------------------------*/
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