skarg
274 lines
7.9 KiB
C
274 lines
7.9 KiB
C
/*####COPYRIGHTBEGIN####
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-------------------------------------------
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Copyright (C) 2007 Steve Karg
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to:
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The Free Software Foundation, Inc.
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59 Temple Place - Suite 330
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Boston, MA 02111-1307
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USA.
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As a special exception, if other files instantiate templates or
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use macros or inline functions from this file, or you compile
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this file and link it with other works to produce a work based
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on this file, this file does not by itself cause the resulting
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work to be covered by the GNU General Public License. However
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the source code for this file must still be made available in
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accordance with section (3) of the GNU General Public License.
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This exception does not invalidate any other reasons why a work
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based on this file might be covered by the GNU General Public
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License.
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-------------------------------------------
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####COPYRIGHTEND####*/
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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 <stdio.h>
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#include <stdlib.h>
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#include <strings.h>
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/* Linux includes */
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <termios.h>
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#include <unistd.h>
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/* Local includes */
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#include "mstp.h"
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/* handle returned from open() */
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static int RS485_Handle = -1;
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/* baudrate settings are defined in <asm/termbits.h>, which is
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included by <termios.h> */
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static unsigned int RS485_Baud = B38400;
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/* serial port name, /dev/ttyS0 */
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static char *RS485_Port_Name = "/dev/ttyS0";
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/* serial I/O settings */
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static struct termios RS485_oldtio;
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#define _POSIX_SOURCE 1 /* POSIX compliant source */
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/*********************************************************************
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* DESCRIPTION: Configures the interface name
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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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/* note: expects a constant char, or char from the heap */
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RS485_Port_Name = ifname;
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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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switch (RS485_Baud) {
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case B19200: return 19200;
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case B38400: return 38400;
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case B57600: return 57600;
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default:
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case B9600: return 9600;
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}
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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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RS485_Baud = B9600;
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break;
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case 19200:
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RS485_Baud = B19200;
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break;
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case 38400:
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RS485_Baud = B38400;
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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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if (valid) {
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/* FIXME: store the baud rate */
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}
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return valid;
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}
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void RS485_Initialize(void)
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{
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struct termios newtio;
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/*
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Open device for reading and writing and not as controlling tty
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because we don't want to get killed if linenoise sends CTRL-C.
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*/
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RS485_Handle = open(RS485_Port_Name, O_RDWR | O_NOCTTY );
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if (RS485_Handle < 0) {
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perror(RS485_Port_Name);
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exit(-1);
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}
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tcgetattr(RS485_Handle,&RS485_oldtio); /* save current serial port settings */
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bzero(&newtio, sizeof(newtio)); /* clear struct for new port settings */
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/*
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BAUDRATE: Set bps rate. You could also use cfsetispeed and cfsetospeed.
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CRTSCTS : output hardware flow control (only used if the cable has
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all necessary lines. See sect. 7 of Serial-HOWTO)
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CS8 : 8n1 (8bit,no parity,1 stopbit)
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CLOCAL : local connection, no modem contol
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CREAD : enable receiving characters
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*/
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newtio.c_cflag = RS485_Baud | CRTSCTS | CS8 | CLOCAL | CREAD;
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/*
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IGNPAR : ignore bytes with parity errors
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ICRNL : map CR to NL (otherwise a CR input on the other computer
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will not terminate input)
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otherwise make device raw (no other input processing)
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*/
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newtio.c_iflag = IGNPAR | ICRNL;
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/*
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Raw output.
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*/
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newtio.c_oflag = 0;
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/*
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ICANON : enable canonical input
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disable all echo functionality, and don't send signals to calling program
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*/
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newtio.c_lflag = ICANON;
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/*
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now clean the modem line and activate the settings for the port
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*/
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tcflush(RS485_Handle, TCIFLUSH);
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tcsetattr(RS485_Handle,TCSANOW,&newtio);
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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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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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ssize_t written = 0;
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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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/*
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On success, the number of bytes written are returned (zero indicates
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nothing was written). On error, -1 is returned, and errno is set
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appropriately. If count is zero and the file descriptor refers to a
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regular file, 0 will be returned without causing any other effect. For
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a special file, the results are not portable.
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*/
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written = write(RS485_Handle, buffer, nbytes);
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/* per MSTP spec, sort of */
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if (mstp_port) {
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mstp_port->SilenceTimer = 0;
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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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uint8_t buf[1];
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int count;
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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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count = read(RS485_Handle,buf,sizeof(buf));
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/* if error, */
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/* ReceiveError = TRUE; */
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/* return; */
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if (count) {
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mstp_port->DataRegister = buf[0];
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/* if data is ready, */
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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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int main(void)
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{
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uint8_t buf[8];
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unsigned i = 0;
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int res;
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RS485_Set_Interface("/dev/ttyS0");
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RS485_Set_Baud_Rate(38400);
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RS485_Initialize();
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for (;;) {
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res = read(RS485_Handle,buf,sizeof(buf));
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/* print any characters received */
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if (res) {
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for (i = 0; i < res; i++) {
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fprintf(stderr,"%02X ",buf[i]);
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}
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}
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res = 0;
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}
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/* restore the old port settings */
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tcsetattr(RS485_Handle,TCSANOW,&RS485_oldtio);
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return 0;
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}
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#endif
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