/* | |
* FreeRTOS Kernel V10.0.1 | |
* Copyright (C) 2017 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 | |
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* 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 | |
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* | |
* http://www.FreeRTOS.org | |
* http://aws.amazon.com/freertos | |
* | |
* 1 tab == 4 spaces! | |
*/ | |
/* | |
BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0. | |
*/ | |
/* Standard includes. */ | |
#include <stdlib.h> | |
/* Scheduler includes. */ | |
#include "FreeRTOS.h" | |
#include "queue.h" | |
/* Demo application includes. */ | |
#include "serial.h" | |
/*-----------------------------------------------------------*/ | |
/* Location of the COM0 registers. */ | |
#define serCOM0 ( ( AT91PS_USART ) AT91C_BASE_US0 ) | |
/* Interrupt control macros. */ | |
#define serINTERRUPT_LEVEL ( 5 ) | |
#define vInterruptOn() AT91F_US_EnableIt( serCOM0, AT91C_US_TXRDY | AT91C_US_RXRDY ) | |
#define vInterruptOff() AT91F_US_DisableIt( serCOM0, AT91C_US_TXRDY ) | |
/* Misc constants. */ | |
#define serINVALID_QUEUE ( ( QueueHandle_t ) 0 ) | |
#define serHANDLE ( ( xComPortHandle ) 1 ) | |
#define serNO_BLOCK ( ( TickType_t ) 0 ) | |
#define serNO_TIMEGUARD ( ( unsigned long ) 0 ) | |
#define serNO_PERIPHERAL_B_SETUP ( ( unsigned long ) 0 ) | |
/* Queues used to hold received characters, and characters waiting to be | |
transmitted. */ | |
static QueueHandle_t xRxedChars; | |
static QueueHandle_t xCharsForTx; | |
/*-----------------------------------------------------------*/ | |
/* Interrupt entry point written in the assembler file serialISR.s79. */ | |
extern void vSerialISREntry( void ); | |
/* The interrupt service routine - called from the assembly entry point. */ | |
__arm void vSerialISR( void ); | |
/*-----------------------------------------------------------*/ | |
/* | |
* See the serial2.h header file. | |
*/ | |
xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength ) | |
{ | |
xComPortHandle xReturn = serHANDLE; | |
extern void ( vUART_ISR )( void ); | |
/* Create the queues used to hold Rx and Tx characters. */ | |
xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) ); | |
xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed char ) ); | |
/* If the queues were created correctly then setup the serial port | |
hardware. */ | |
if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) ) | |
{ | |
portENTER_CRITICAL(); | |
{ | |
/* Enable the USART clock. */ | |
AT91F_PMC_EnablePeriphClock( AT91C_BASE_PMC, 1 << AT91C_ID_US0 ); | |
AT91F_PIO_CfgPeriph( AT91C_BASE_PIOA, ( ( unsigned long ) AT91C_PA5_RXD0 ) | ( ( unsigned long ) AT91C_PA6_TXD0 ), serNO_PERIPHERAL_B_SETUP ); | |
/* Set the required protocol. */ | |
AT91F_US_Configure( serCOM0, configCPU_CLOCK_HZ, AT91C_US_ASYNC_MODE, ulWantedBaud, serNO_TIMEGUARD ); | |
/* Enable Rx and Tx. */ | |
serCOM0->US_CR = AT91C_US_RXEN | AT91C_US_TXEN; | |
/* Enable the Rx interrupts. The Tx interrupts are not enabled | |
until there are characters to be transmitted. */ | |
AT91F_US_EnableIt( serCOM0, AT91C_US_RXRDY ); | |
/* Enable the interrupts in the AIC. */ | |
AT91F_AIC_ConfigureIt( AT91C_BASE_AIC, AT91C_ID_US0, serINTERRUPT_LEVEL, AT91C_AIC_SRCTYPE_INT_LEVEL_SENSITIVE, ( void (*)( void ) ) vSerialISREntry ); | |
AT91F_AIC_EnableIt( AT91C_BASE_AIC, AT91C_ID_US0 ); | |
} | |
portEXIT_CRITICAL(); | |
} | |
else | |
{ | |
xReturn = ( xComPortHandle ) 0; | |
} | |
/* This demo file only supports a single port but we have to return | |
something to comply with the standard demo header file. */ | |
return xReturn; | |
} | |
/*-----------------------------------------------------------*/ | |
signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, TickType_t xBlockTime ) | |
{ | |
/* The port handle is not required as this driver only supports one port. */ | |
( 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 pdTRUE; | |
} | |
else | |
{ | |
return pdFALSE; | |
} | |
} | |
/*-----------------------------------------------------------*/ | |
void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength ) | |
{ | |
signed char *pxNext; | |
/* A couple of parameters that this port does not use. */ | |
( void ) usStringLength; | |
( void ) pxPort; | |
/* NOTE: This implementation does not handle the queue being full as no | |
block time is used! */ | |
/* The port handle is not required as this driver only supports UART0. */ | |
( void ) pxPort; | |
/* Send each character in the string, one at a time. */ | |
pxNext = ( signed char * ) pcString; | |
while( *pxNext ) | |
{ | |
xSerialPutChar( pxPort, *pxNext, serNO_BLOCK ); | |
pxNext++; | |
} | |
} | |
/*-----------------------------------------------------------*/ | |
signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, TickType_t xBlockTime ) | |
{ | |
/* Place the character in the queue of characters to be transmitted. */ | |
if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS ) | |
{ | |
return pdFAIL; | |
} | |
/* 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. */ | |
vInterruptOn(); | |
return pdPASS; | |
} | |
/*-----------------------------------------------------------*/ | |
void vSerialClose( xComPortHandle xPort ) | |
{ | |
/* Not supported as not required by the demo application. */ | |
} | |
/*-----------------------------------------------------------*/ | |
/* Serial port ISR. This can cause a context switch so is not defined as a | |
standard ISR using the __irq keyword. Instead a wrapper function is defined | |
within serialISR.s79 which in turn calls this function. See the port | |
documentation on the FreeRTOS.org website for more information. */ | |
__arm void vSerialISR( void ) | |
{ | |
unsigned long ulStatus; | |
signed char cChar; | |
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE; | |
/* What caused the interrupt? */ | |
ulStatus = serCOM0->US_CSR &= serCOM0->US_IMR; | |
if( ulStatus & AT91C_US_TXRDY ) | |
{ | |
/* The interrupt was caused by the THR becoming empty. Are there any | |
more characters to transmit? */ | |
if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE ) | |
{ | |
/* A character was retrieved from the queue so can be sent to the | |
THR now. */ | |
serCOM0->US_THR = cChar; | |
} | |
else | |
{ | |
/* Queue empty, nothing to send so turn off the Tx interrupt. */ | |
vInterruptOff(); | |
} | |
} | |
if( ulStatus & AT91C_US_RXRDY ) | |
{ | |
/* The interrupt was caused by a character being received. Grab the | |
character from the RHR and place it in the queue or received | |
characters. */ | |
cChar = serCOM0->US_RHR; | |
xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken ); | |
} | |
/* If a task was woken by either a character being received or a character | |
being transmitted then we may need to switch to another task. */ | |
portEND_SWITCHING_ISR( xHigherPriorityTaskWoken ); | |
/* End the interrupt in the AIC. */ | |
AT91C_BASE_AIC->AIC_EOICR = 0; | |
} | |