/* | |
* FreeRTOS Kernel V10.0.0 | |
* Copyright (C) 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved. | |
* | |
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* subject to the following conditions: | |
* | |
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* | |
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* 1 tab == 4 spaces! | |
*/ | |
/* | |
BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0. | |
*NOTE* - This file is designed to test some of the RTOS features - it is | |
not intended to represent an efficient implementation! | |
*/ | |
/* Standard includes. */ | |
#include <stdlib.h> | |
/* Scheduler includes. */ | |
#include "FreeRTOS.h" | |
#include "queue.h" | |
/* Demo application includes. */ | |
#include "serial.h" | |
/* Hardware specifics. */ | |
#define serRX_DATA_PIN ( 0x01 ) | |
#define serTX_DATA_PIN ( 0x02 ) | |
#define serCLOCK_Fxx_DIV_8 0x03 | |
#define serUPWR ( 0x80 ) | |
#define serUTXE ( 0x40 ) | |
#define serURXE ( 0x20 ) | |
#define serUCL ( 0x02 ) | |
#define serLSB ( 0x10 ) | |
/* Misc. */ | |
#define serINVALID_QUEUE ( ( QueueHandle_t ) 0 ) | |
#define serHANDLE ( ( xComPortHandle ) 1 ) | |
#define serNO_BLOCK ( ( TickType_t ) 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.s85. */ | |
extern void vSerialISREntry( void ); | |
/* Flag to indicate whether or not there are characters already queued to send. */ | |
static volatile unsigned long ulTxInProgress = pdFALSE; | |
/*-----------------------------------------------------------*/ | |
/* | |
* See the serial2.h header file. | |
*/ | |
xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength ) | |
{ | |
xComPortHandle xReturn = serHANDLE; | |
const unsigned long ulFuclk = ( configCPU_CLOCK_HZ / 2 ) / 8UL; | |
/* 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(); | |
{ | |
/* Set the UART0 Rx and Tx pins to their alternative function. */ | |
PMC3 |= ( serRX_DATA_PIN | serTX_DATA_PIN ); | |
PM3 &= ~( serTX_DATA_PIN ); | |
/* Setup clock for required baud. */ | |
UD0CTL1 = serCLOCK_Fxx_DIV_8; | |
UD0CTL2 = ulFuclk / ( 2 * ulWantedBaud ); | |
/* Enable, n81. */ | |
UD0CTL0 = ( serUPWR | serUTXE | serURXE | serUCL | serLSB ); | |
/* Enable interrupts for both Rx and Tx. */ | |
UD0TIC = 0x07; | |
UD0RIC = 0x07; | |
ulTxInProgress = pdFALSE; | |
} | |
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 ) | |
{ | |
portBASE_TYPE xReturn = pdPASS; | |
portENTER_CRITICAL(); | |
{ | |
/* There are currently no characters queued up to send so write the | |
character directly to the UART. */ | |
if( ulTxInProgress == pdFALSE ) | |
{ | |
UD0TX = cOutChar; | |
ulTxInProgress = pdTRUE; | |
} | |
else | |
{ | |
/* The UART is already busy so write the character to the Tx queue. | |
The queue is drained from within the Tx interrupt. */ | |
if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS ) | |
{ | |
xReturn = pdFAIL; | |
} | |
} | |
} | |
portEXIT_CRITICAL(); | |
return xReturn; | |
} | |
/*-----------------------------------------------------------*/ | |
void vSerialClose( xComPortHandle xPort ) | |
{ | |
/* Not supported as not required by the demo application. */ | |
} | |
/*-----------------------------------------------------------*/ | |
/* Tx interrupt handler. This is called from the asm file wrapper. */ | |
void vUARTTxISRHandler( void ) | |
{ | |
char cChar; | |
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE; | |
/* Are there any more characters queue to transmit? */ | |
if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE ) | |
{ | |
/* Send the next character. */ | |
UD0TX = cChar; | |
} | |
else | |
{ | |
/* The UART is no longer active. */ | |
ulTxInProgress = pdFALSE; | |
} | |
/* If reading a character from the Rx queue caused a task to unblock, and | |
the unblocked task has a priority higher than the currently running task, | |
then xHigherPriorityTaskWoken will have been set to true and a context | |
switch should occur now. */ | |
portYIELD_FROM_ISR( xHigherPriorityTaskWoken ); | |
} | |
/*-----------------------------------------------------------*/ | |
/* Rx interrupt handler. This is called from the asm file wrapper. */ | |
void vUARTRxISRHandler( void ) | |
{ | |
char cChar; | |
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE; | |
/* Send the received character to the Rx queue. */ | |
cChar = UD0RX; | |
xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken ); | |
/* If sending a character to the Tx queue caused a task to unblock, and | |
the unblocked task has a priority higher than the currently running task, | |
then xHigherPriorityTaskWoken will have been set to true and a context | |
switch should occur now. */ | |
portYIELD_FROM_ISR( xHigherPriorityTaskWoken ); | |
} | |