Added port for Atmel AT91SAM7S-EK ARM7 board using the YAGARTO GNU ARM tool suite. Still testing.
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skarg
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/**************************************************************************
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*
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* Copyright (C) 2007 Steve Karg <skarg@users.sourceforge.net>
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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*********************************************************************/
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/* The module handles sending data out the RS-485 port */
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/* and handles receiving data from the RS-485 port. */
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/* Customize this file for your specific hardware */
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#include <stddef.h>
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#include <stdint.h>
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#include <stdbool.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include "mstp.h"
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/* This file has been customized for use with UART0
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on the AT91SAM7S-EK */
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#include "board.h"
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/* UART */
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static AT91S_USART *RS485_Interface = AT91C_BASE_US0;
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/* baud rate */
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static int RS485_Baud = 38400;
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/****************************************************************************
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* DESCRIPTION: Sets the interface - UART0 or UART1 or...
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* RETURN: none
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* ALGORITHM: none
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* NOTES: none
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*****************************************************************************/
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void RS485_Set_Interface(char *ifname)
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{
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RS485_Interface = (AT91S_USART *)ifname;
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}
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/****************************************************************************
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* DESCRIPTION: Initializes the RS485 hardware and variables, and starts in
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* receive mode.
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* RETURN: none
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* ALGORITHM: none
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* NOTES: none
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*****************************************************************************/
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void RS485_Initialize(void)
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{
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// enable the USART0 peripheral clock
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volatile AT91PS_PMC pPMC = AT91C_BASE_PMC;
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pPMC->PMC_PCER = pPMC->PMC_PCSR | (1<<AT91C_ID_US0);
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/* enable the peripheral by disabling the pin in the PIO controller */
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*AT91C_PIOA_PDR = AT91C_PA5_RXD0 | AT91C_PA6_TXD0 | AT91C_PA7_RTS0;
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RS485_Interface->US_CR =
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AT91C_US_RSTRX | /* Reset Receiver */
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AT91C_US_RSTTX | /* Reset Transmitter */
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AT91C_US_RXDIS | /* Receiver Disable */
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AT91C_US_TXDIS; /* Transmitter Disable */
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RS485_Interface->US_MR =
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AT91C_US_USMODE_RS485 | /* RS-485 Mode - RTS auto asserted */
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AT91C_US_CLKS_CLOCK | /* Clock = MCK */
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AT91C_US_CHRL_8_BITS | /* 8-bit Data */
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AT91C_US_PAR_NONE | /* No Parity */
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AT91C_US_NBSTOP_1_BIT; /* 1 Stop Bit */
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/* set the Time Guard to release RTS after x bit times */
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RS485_Interface->US_TTGR = 4;
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/* baud rate */
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RS485_Interface->US_BRGR = MCK/16/RS485_Baud;
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RS485_Interface->US_CR =
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AT91C_US_RXEN | /* Receiver Enable */
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AT91C_US_TXEN; /* Transmitter Enable */
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return;
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}
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void RS485_Cleanup(void)
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{
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}
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/****************************************************************************
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* DESCRIPTION: Returns the baud rate that we are currently running at
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* RETURN: none
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* ALGORITHM: none
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* NOTES: none
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*****************************************************************************/
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uint32_t RS485_Get_Baud_Rate(void)
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{
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return RS485_Baud;
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}
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/****************************************************************************
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* DESCRIPTION: Sets the baud rate for the chip USART
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* RETURN: none
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* ALGORITHM: none
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* NOTES: none
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*****************************************************************************/
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bool RS485_Set_Baud_Rate(uint32_t baud)
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{
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bool valid = true;
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switch (baud) {
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case 9600:
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case 19200:
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case 38400:
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case 57600:
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case 115200:
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RS485_Baud = baud;
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RS485_Interface->US_BRGR = MCK/16/baud;
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/* FIXME: store the baud rate */
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break;
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default:
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valid = false;
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break;
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}
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return valid;
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}
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/* Transmits a Frame on the wire */
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void RS485_Send_Frame(
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volatile struct mstp_port_struct_t *mstp_port, /* port specific data */
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uint8_t * buffer, /* frame to send (up to 501 bytes of data) */
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uint16_t nbytes) /* number of bytes of data (up to 501) */
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{
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uint8_t turnaround_time;
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uint32_t baud;
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/* toggle LED on send */
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volatile AT91PS_PIO pPIO = AT91C_BASE_PIOA;
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if ((pPIO->PIO_ODSR & LED1) == LED1)
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pPIO->PIO_CODR = LED1;
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else
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pPIO->PIO_SODR = LED1;
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/* delay after reception - per MS/TP spec */
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if (mstp_port) {
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baud = RS485_Get_Baud_Rate();
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/* wait about 40 bit times since reception */
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if (baud == 9600)
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turnaround_time = 4;
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else if (baud == 19200)
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turnaround_time = 2;
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else
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turnaround_time = 1;
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while (mstp_port->SilenceTimer < turnaround_time) {
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/* do nothing - wait for timer to increment */
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};
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}
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while (nbytes) {
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while (!(RS485_Interface->US_CSR & AT91C_US_TXRDY)) {
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/* do nothing - wait for Tx buffer to get empty */
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}
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RS485_Interface->US_THR = *buffer;
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buffer++;
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nbytes--;
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/* per MSTP spec */
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if (mstp_port) {
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mstp_port->SilenceTimer = 0;
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}
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}
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return;
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}
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/* called by timer, interrupt(?) or other thread */
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void RS485_Check_UART_Data(struct mstp_port_struct_t *mstp_port)
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{
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if (mstp_port->ReceiveError == true) {
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/* wait for state machine to clear this */
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}
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/* wait for state machine to read from the DataRegister */
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else if (mstp_port->DataAvailable == false) {
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/* check for data */
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if ( RS485_Interface->US_CSR & AT91C_US_RXRDY) {
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mstp_port->DataRegister = RS485_Interface->US_RHR;
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mstp_port->DataAvailable = true;
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}
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}
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}
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#ifdef TEST_RS485
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static struct mstp_port_struct_t MSTP_Port;
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int main(void)
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{
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unsigned i = 0;
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RS485_Set_Baud_Rate(38400);
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RS485_Initialize();
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/* receive task */
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for (;;) {
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RS485_Check_UART_Data(&MSTP_Port);
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if (MSTP_Port.DataAvailable) {
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fprintf(stderr,"%02X ",MSTP_Port.DataRegister);
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MSTP_Port.DataAvailable = false;
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}
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}
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}
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#endif /* TEST_ABORT */
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