From 9baa11df1805fbf179cf1f76e1b7a54f2ae79a42 Mon Sep 17 00:00:00 2001
From: Rostislav Lisovy <lisovy@gmail.com>
Date: Wed, 9 Nov 2011 18:12:26 +0100
Subject: [PATCH] LIN master simulated with an UART.

Slaves (PCAN-LIN and PCAN-USB Pro) are responding only when this master works with B2400 speed.
---
 misc/tty_lin_master/Makefile |   2 +
 misc/tty_lin_master/main.c   | 166 +++++++++++++++++++++++++++++++++++
 2 files changed, 168 insertions(+)
 create mode 100644 misc/tty_lin_master/Makefile
 create mode 100644 misc/tty_lin_master/main.c

diff --git a/misc/tty_lin_master/Makefile b/misc/tty_lin_master/Makefile
new file mode 100644
index 0000000..6bf535a
--- /dev/null
+++ b/misc/tty_lin_master/Makefile
@@ -0,0 +1,2 @@
+all: main.c
+	gcc main.c -std=gnu99 -Wall -pedantic -o main
diff --git a/misc/tty_lin_master/main.c b/misc/tty_lin_master/main.c
new file mode 100644
index 0000000..a61566c
--- /dev/null
+++ b/misc/tty_lin_master/main.c
@@ -0,0 +1,166 @@
+/*
+ * PCAN-LIN, RS-232 to CAN/LIN converter control application
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <termios.h>
+#include <stdint.h>
+
+#define UART_SPEED		B2400
+
+#define LIN_HDR_SIZE		2
+#define LIN_PKT_MAX_SIZE	16 /* FIXME */
+struct termios term_attr;
+/* ------------------------------------------------------------------------ */
+static void reset_input_mode(int tty)
+{
+	tcsetattr(tty, TCSANOW, &term_attr);
+}
+
+static void set_input_mode(int tty, speed_t speed)
+{
+	int status;
+	struct termios tattr;
+
+	/* Flush input and output queues. */
+	if (tcflush(tty, TCIOFLUSH) != 0) {
+		perror("tcflush");
+		exit(EXIT_FAILURE);
+	}
+
+	/* Fetch the current terminal parameters. */
+	if(!isatty(tty)) {
+		fprintf(stderr, "Not a terminal.\n");
+		exit(EXIT_FAILURE);
+	}
+
+	/* Save settings for later restoring */
+	tcgetattr(tty, &term_attr);
+
+	/* RAW mode */
+	tcgetattr(tty, &tattr);
+	tattr.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP
+				| INLCR | IGNCR | ICRNL | IXON);
+	tattr.c_oflag &= ~OPOST;
+	tattr.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
+	tattr.c_cflag &= ~(CSIZE | PARENB);
+	tattr.c_cflag |= CS8;
+
+	tattr.c_cc[VMIN] = 1;
+	tattr.c_cc[VTIME] = 0;
+
+	/* Set TX, RX speed */
+	cfsetispeed(&tattr, speed);
+	cfsetospeed(&tattr, speed);
+
+	status = tcsetattr(tty, TCSANOW, &tattr);
+	if (status == -1)
+		perror("tcsetattr()");
+
+}
+
+
+int send_header(int tty)
+{
+	struct termios tattr;
+	int buff[3];
+	buff[0] = 0x00; /* Sync byte */
+	buff[1] = 0x55; /* Sync byte */
+	buff[2] = 0xC1; /* LIN ID: 1 */
+
+
+	/* Decrease speed to send BREAK (simulated with 0x00 data frame)*/	
+	tcgetattr(tty, &tattr);
+	cfsetospeed(&tattr, B1200);
+	tcsetattr(tty, TCSADRAIN, &tattr);
+
+	write(tty, &buff[0], 1);
+
+	cfsetospeed(&tattr, UART_SPEED);
+	tcsetattr(tty, TCSADRAIN, &tattr);
+
+	//tcsendbreak(tty, 1);	 /* Break */
+	//usleep((useconds_t) 50); /* Break Delimiter */
+	write(tty, &buff[1], 1); /* Sync Byte Field */
+	write(tty, &buff[2], 1); /* PID -- Protected Identifier Field */
+	return 0;
+}
+
+int read_header(int tty)
+{
+	int p0, p1; /* Parity bits */
+	int par_rec; /* Parity received as a part of a packet */
+	int par_calc; /* Calculated parity */
+	int received = 0;
+	uint8_t buff[LIN_HDR_SIZE];
+	memset(buff, '\0', sizeof(buff));
+
+	while (1) {
+		received = read(tty, &buff[0], 1);
+		if (received == -1)
+			perror("read()");
+		
+		if (buff[0] != 0x55) /* Sync byte field */
+			continue;
+
+		received = read(tty, &buff[1], 1);
+		if (received == -1)
+			perror("read()");
+		else
+			break;
+	}
+
+	p0 = (buff[1] ^ (buff[1] >> 1) ^ (buff[1] >> 2) ^ (buff[1] >> 4)) & 0x1;
+	p1 = ~(((buff[1] >> 1) ^ (buff[1] >> 3) ^ (buff[1] >> 4) ^ (buff[1] >> 5))) & 0x1;
+
+	printf("%02X ", buff[0]);
+	printf("%02X ", buff[1]);
+
+	par_rec = (buff[1] & 0xc0) >> 6;
+	par_calc = p0 | (p1 << 1);
+	printf("| LIN id: %02X ", buff[1] & 0x3f);
+	//printf("| par_rec: %X; par_calc: %X ", par_rec, par_calc);
+	if (par_rec == par_calc)
+		printf("| parity OK");
+	
+	printf("\n");
+
+	return 0;
+}
+
+
+int main(int argc, char* argv[])
+{
+	char dev[32];
+	int tty;
+
+	if (argc < 2) {
+		fprintf(stderr, "Device is missing\n");
+		fprintf(stderr, "Usage: %s DEVICE\n", argv[0]);
+		return -3;
+	}
+
+	strncpy((char*)&dev, argv[1], 32);
+	tty = open(dev, O_RDWR);
+	if (tty < 0) {
+		perror("open()");
+		return -4;
+	}
+
+	/* Configure UART */
+	set_input_mode(tty, UART_SPEED);
+
+	while(1) {
+		send_header(tty);
+		sleep(1);
+	}	
+
+	reset_input_mode(tty);
+    	close(tty);
+
+	return EXIT_SUCCESS;
+}
-- 
2.39.2