/* | |
* FreeRTOS Kernel V10.3.0 | |
* 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 | |
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* subject to the following conditions: | |
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* | |
* http://www.FreeRTOS.org | |
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*/ | |
/* 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; | |
} | |
/*-----------------------------------------------------------*/ | |