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379 lines
12 KiB
C
379 lines
12 KiB
C
/*This file has been prepared for Doxygen automatic documentation generation.*/
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/*! \file *********************************************************************
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*
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* \brief FreeRTOS Serial Port management example for AVR32 UC3.
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*
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* - Compiler: IAR EWAVR32 and GNU GCC for AVR32
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* - Supported devices: All AVR32 devices can be used.
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* - AppNote:
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*
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* \author Atmel Corporation: http://www.atmel.com \n
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* Support and FAQ: http://support.atmel.no/
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*
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*****************************************************************************/
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/* Copyright (c) 2007, Atmel Corporation All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* 3. The name of ATMEL may not be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY ATMEL ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY AND
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* SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT,
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* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR USART.
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*/
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/* Scheduler includes. */
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#include "FreeRTOS.h"
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#include "queue.h"
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#include "task.h"
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/* Demo application includes. */
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#include "serial.h"
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#include <avr32/io.h>
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#include "board.h"
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#include "gpio.h"
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/*-----------------------------------------------------------*/
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/* Constants to setup and access the USART. */
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#define serINVALID_COMPORT_HANDLER ( ( xComPortHandle ) 0 )
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#define serINVALID_QUEUE ( ( xQueueHandle ) 0 )
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#define serHANDLE ( ( xComPortHandle ) 1 )
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#define serNO_BLOCK ( ( portTickType ) 0 )
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/*-----------------------------------------------------------*/
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/* Queues used to hold received characters, and characters waiting to be
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transmitted. */
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static xQueueHandle xRxedChars;
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static xQueueHandle xCharsForTx;
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/*-----------------------------------------------------------*/
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/* Forward declaration. */
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static void vprvSerialCreateQueues( unsigned portBASE_TYPE uxQueueLength,
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xQueueHandle *pxRxedChars,
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xQueueHandle *pxCharsForTx );
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/*-----------------------------------------------------------*/
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#if __GNUC__
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__attribute__((__noinline__))
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#elif __ICCAVR32__
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#pragma optimize = no_inline
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#endif
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static portBASE_TYPE prvUSART_ISR_NonNakedBehaviour( void )
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{
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/* Now we can declare the local variables. */
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signed portCHAR cChar;
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portBASE_TYPE xTaskWokenByTx = pdFALSE, xTaskWokenByRx = pdFALSE;
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unsigned portLONG ulStatus;
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volatile avr32_usart_t *usart = serialPORT_USART;
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portBASE_TYPE retstatus;
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/* What caused the interrupt? */
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ulStatus = usart->csr & usart->imr;
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if (ulStatus & AVR32_USART_CSR_TXRDY_MASK)
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{
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/* The interrupt was caused by the THR becoming empty. Are there any
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more characters to transmit?
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Because FreeRTOS is not supposed to run with nested interrupts, put all OS
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calls in a critical section . */
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portENTER_CRITICAL();
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retstatus = xQueueReceiveFromISR( xCharsForTx, &cChar, &xTaskWokenByTx );
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portEXIT_CRITICAL();
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if (retstatus == pdTRUE)
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{
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/* A character was retrieved from the queue so can be sent to the
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THR now. */
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usart->thr = cChar;
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}
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else
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{
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/* Queue empty, nothing to send so turn off the Tx interrupt. */
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usart->idr = AVR32_USART_IDR_TXRDY_MASK;
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}
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}
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if (ulStatus & AVR32_USART_CSR_RXRDY_MASK)
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{
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/* The interrupt was caused by the receiver getting data. */
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cChar = usart->rhr; //TODO
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/* Because FreeRTOS is not supposed to run with nested interrupts, put all OS
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calls in a critical section . */
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portENTER_CRITICAL();
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retstatus = xQueueSendFromISR(xRxedChars, &cChar, pdFALSE);
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portEXIT_CRITICAL();
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if( retstatus )
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{
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xTaskWokenByRx = pdTRUE;
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}
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}
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/* The return value will be used by portEXIT_SWITCHING_ISR() to know if it
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should perform a vTaskSwitchContext(). */
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return ( xTaskWokenByTx || xTaskWokenByRx );
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}
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/*-----------------------------------------------------------*/
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/*
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* USART interrupt service routine.
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*/
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#if __GNUC__
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__attribute__((__naked__))
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#elif __ICCAVR32__
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#pragma shadow_registers = full // Naked.
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#endif
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static void vUSART_ISR( void )
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{
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/* This ISR can cause a context switch, so the first statement must be a
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call to the portENTER_SWITCHING_ISR() macro. This must be BEFORE any
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variable declarations. */
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portENTER_SWITCHING_ISR();
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prvUSART_ISR_NonNakedBehaviour();
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/* Exit the ISR. If a task was woken by either a character being received
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or transmitted then a context switch will occur. */
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portEXIT_SWITCHING_ISR();
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}
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/*-----------------------------------------------------------*/
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/*
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* Init the serial port for the Minimal implementation.
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*/
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xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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{
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static const gpio_map_t USART_GPIO_MAP =
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{
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{ serialPORT_USART_RX_PIN, serialPORT_USART_RX_FUNCTION },
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{ serialPORT_USART_TX_PIN, serialPORT_USART_TX_FUNCTION }
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};
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xComPortHandle xReturn = serHANDLE;
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volatile avr32_usart_t *usart = serialPORT_USART;
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int cd; /* USART Clock Divider. */
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/* Create the rx and tx queues. */
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vprvSerialCreateQueues( uxQueueLength, &xRxedChars, &xCharsForTx );
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/* Configure USART. */
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if( ( xRxedChars != serINVALID_QUEUE ) &&
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( xCharsForTx != serINVALID_QUEUE ) &&
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( ulWantedBaud != ( unsigned portLONG ) 0 ) )
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{
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portENTER_CRITICAL();
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{
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/**
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** Reset USART.
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**/
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/* Disable all USART interrupt sources to begin... */
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usart->idr = 0xFFFFFFFF;
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/* Reset mode and other registers that could cause unpredictable
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behaviour after reset */
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usart->mr = 0; /* Reset Mode register. */
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usart->rtor = 0; /* Reset Receiver Time-out register. */
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usart->ttgr = 0; /* Reset Transmitter Timeguard register. */
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/* Shutdown RX and TX, reset status bits, reset iterations in CSR, reset NACK
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and turn off DTR and RTS */
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usart->cr = AVR32_USART_CR_RSTRX_MASK |
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AVR32_USART_CR_RSTTX_MASK |
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AVR32_USART_CR_RXDIS_MASK |
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AVR32_USART_CR_TXDIS_MASK |
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AVR32_USART_CR_RSTSTA_MASK |
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AVR32_USART_CR_RSTIT_MASK |
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AVR32_USART_CR_RSTNACK_MASK |
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AVR32_USART_CR_DTRDIS_MASK |
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AVR32_USART_CR_RTSDIS_MASK;
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/**
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** Configure USART.
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**/
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/* Enable USART RXD & TXD pins. */
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gpio_enable_module( USART_GPIO_MAP, sizeof( USART_GPIO_MAP ) / sizeof( USART_GPIO_MAP[0] ) );
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/* Set the USART baudrate to be as close as possible to the wanted baudrate. */
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/*
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* ** BAUDRATE CALCULATION **
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*
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* Selected Clock Selected Clock
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* baudrate = ---------------- or baudrate = ----------------
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* 16 x CD 8 x CD
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*
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* (with 16x oversampling) (with 8x oversampling)
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*/
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if( ulWantedBaud < ( configCPU_CLOCK_HZ / 16 ) )
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{
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/* Use 8x oversampling */
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usart->mr |= (1<<AVR32_USART_MR_OVER_OFFSET);
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cd = configCPU_CLOCK_HZ / (8*ulWantedBaud);
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if( cd < 2 )
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{
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return serINVALID_COMPORT_HANDLER;
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}
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usart->brgr = (cd << AVR32_USART_BRGR_CD_OFFSET);
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}
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else
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{
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/* Use 16x oversampling */
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usart->mr &= ~(1<<AVR32_USART_MR_OVER_OFFSET);
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cd = configCPU_CLOCK_HZ / (16*ulWantedBaud);
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if( cd > 65535 )
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{
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/* Baudrate is too low */
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return serINVALID_COMPORT_HANDLER;
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}
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}
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usart->brgr = (cd << AVR32_USART_BRGR_CD_OFFSET);
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/* Set the USART Mode register: Mode=Normal(0), Clk selection=MCK(0),
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CHRL=8, SYNC=0(asynchronous), PAR=None, NBSTOP=1, CHMODE=0, MSBF=0,
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MODE9=0, CKLO=0, OVER(previously done when setting the baudrate),
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other fields not used in this mode. */
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usart->mr |= ((8-5) << AVR32_USART_MR_CHRL_OFFSET ) |
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( 4 << AVR32_USART_MR_PAR_OFFSET ) |
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( 1 << AVR32_USART_MR_NBSTOP_OFFSET);
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/* Write the Transmit Timeguard Register */
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usart->ttgr = 0;
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/* Register the USART interrupt handler to the interrupt controller and
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enable the USART interrupt. */
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INTC_register_interrupt((__int_handler)&vUSART_ISR, serialPORT_USART_IRQ, INT1);
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/* Enable USART interrupt sources (but not Tx for now)... */
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usart->ier = AVR32_USART_IER_RXRDY_MASK;
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/* Enable receiver and transmitter... */
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usart->cr |= AVR32_USART_CR_TXEN_MASK | AVR32_USART_CR_RXEN_MASK;
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}
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portEXIT_CRITICAL();
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}
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else
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{
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xReturn = serINVALID_COMPORT_HANDLER;
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}
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return xReturn;
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}
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/*-----------------------------------------------------------*/
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signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
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{
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/* The port handle is not required as this driver only supports UART0. */
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( void ) pxPort;
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/* Get the next character from the buffer. Return false if no characters
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are available, or arrive before xBlockTime expires. */
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if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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{
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return pdTRUE;
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}
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else
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{
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return pdFALSE;
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}
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}
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/*-----------------------------------------------------------*/
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void vSerialPutString( xComPortHandle pxPort, const signed portCHAR * const pcString, unsigned portSHORT usStringLength )
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{
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signed portCHAR *pxNext;
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/* NOTE: This implementation does not handle the queue being full as no
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block time is used! */
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/* The port handle is not required as this driver only supports UART0. */
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( void ) pxPort;
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/* Send each character in the string, one at a time. */
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pxNext = ( signed portCHAR * ) pcString;
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while( *pxNext )
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{
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xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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pxNext++;
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}
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}
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/*-----------------------------------------------------------*/
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signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
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{
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volatile avr32_usart_t *usart = serialPORT_USART;
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/* Place the character in the queue of characters to be transmitted. */
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if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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{
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return pdFAIL;
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}
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/* Turn on the Tx interrupt so the ISR will remove the character from the
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queue and send it. This does not need to be in a critical section as
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if the interrupt has already removed the character the next interrupt
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will simply turn off the Tx interrupt again. */
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usart->ier = (1 << AVR32_USART_IER_TXRDY_OFFSET);
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return pdPASS;
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}
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/*-----------------------------------------------------------*/
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void vSerialClose( xComPortHandle xPort )
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{
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/* Not supported as not required by the demo application. */
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}
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/*-----------------------------------------------------------*/
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/*###########################################################*/
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/*
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* Create the rx and tx queues.
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*/
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static void vprvSerialCreateQueues( unsigned portBASE_TYPE uxQueueLength, xQueueHandle *pxRxedChars, xQueueHandle *pxCharsForTx )
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{
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/* Create the queues used to hold Rx and Tx characters. */
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xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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/* Pass back a reference to the queues so the serial API file can
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post/receive characters. */
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*pxRxedChars = xRxedChars;
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*pxCharsForTx = xCharsForTx;
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}
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/*-----------------------------------------------------------*/
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