etisserant@0: #include <stdio.h>
etisserant@0: #include <stdlib.h>
etisserant@0: 
etisserant@0: 
etisserant@0: /*
etisserant@0: 	CiA DS-301, p.20
etisserant@0: */
etisserant@0: #define MAX_BIT_TIMING 9
etisserant@0: int table_bit_timing_settings[MAX_BIT_TIMING][3] =
etisserant@0: {
etisserant@0: 	{1000, 8, 6}, /* baudrate, number of time quanta per bit, tsync+tseg1 */
etisserant@0: 	{800, 10, 8},
etisserant@0: 	{500, 16, 14},
etisserant@0: 	{250, 16, 14},
etisserant@0: 	{125, 16, 14},
etisserant@0: 	{100, 16, 14},
etisserant@0: 	{ 50, 16, 14},
etisserant@0: 	{ 25, 16, 14},
etisserant@0: 	{ 10, 16, 14}
etisserant@0: };
etisserant@0: 
etisserant@0: 
etisserant@0: void can_timing_registers(double f, int *v)
etisserant@0: /* fill the vector v with the proper setting for TIMER 0 and TIMER 1
etisserant@0:    regarding the clock and the baudrate */
etisserant@0: {
etisserant@0: 	int i;
etisserant@0: 
etisserant@0: 	int BRP, TSEG1, TSEG2;
etisserant@0: 
etisserant@0: 	double nominal, tq, tscl;
etisserant@0: 
etisserant@0: 	double tclk = 1 / (f*1e6); /* sec */
etisserant@0: 
etisserant@0: 	for(i=0; i<MAX_BIT_TIMING; i++)
etisserant@0: 	{
etisserant@0: 		nominal = 1. / (table_bit_timing_settings[i][0]*1e3); /* nominal bit time */
etisserant@0: 
etisserant@0: 		tq = nominal / table_bit_timing_settings[i][1]; /* time quanta */
etisserant@0: 
etisserant@0: 		tscl = tq; /* Tsyncseg = Tscl (ref. SJA 1000 datasheet, p.51) */
etisserant@0: 
etisserant@0: 		/* tcsl = 2 tclk (BRP + 1) */
etisserant@0: 		BRP = (int)(tscl / (2. * tclk) - 1.);
etisserant@0: 
etisserant@0: 		/* 
etisserant@0: 			BRT0 = SJW * 64 + BRP 
etisserant@0: 			SJW : synchonisation jump Width, user defined (0..3)
etisserant@0: 		*/
etisserant@0: 
etisserant@0: 		/* tseg1 = tscl * (TSEG1 + 1) */
etisserant@0: 		TSEG1 = (int)((table_bit_timing_settings[i][2] - 1)*tq/tscl - 1.);
etisserant@0: 
etisserant@0: 		/* tseg2 = tscl * (TSEG2 + 1) */
etisserant@0: 		TSEG2 = (int)(2.*tq/tscl - 1.);
etisserant@0: 
etisserant@0: 		/*
etisserant@0: 			BRT1 = SAM*128 + TSEG2*16 + TSEG1
etisserant@0: 			SAM = Sampling (0 = single sampling, 1 = triple sampling)
etisserant@0: 		*/
etisserant@0: 
etisserant@0: 		if (BRP < 64)
etisserant@0: 		{
etisserant@0: 			v[2*i] = BRP;
etisserant@0: 			v[2*i+1] = TSEG1+16*TSEG2;
etisserant@0: 		}
etisserant@0: 		else
etisserant@0: 		{
etisserant@0: 			v[2*i] = 0;
etisserant@0: 			v[2*i+1] = 0;
etisserant@0: 		}
etisserant@0: 	}
etisserant@0: }
etisserant@0: 
etisserant@0: 
etisserant@0: void print_header(double frequency, /* clock rate in MHz*/
etisserant@0:                   int    sjw)       /* 0..3 */
etisserant@0: {
etisserant@0: 	int i, array[18];
etisserant@0: 	FILE *f = fopen("baudrate_table.h", "w");
etisserant@0: 
etisserant@0: 	can_timing_registers(frequency, array);
etisserant@0: 
etisserant@0: 	fprintf(f, "#if !defined(_BAUDRATE_TABLE_H_)\n");
etisserant@0: 	fprintf(f, "#define _BAUDRATE_TABLE_H_\n");
etisserant@0: 	fprintf(f, "\n");
etisserant@0: 	fprintf(f, "/*\n");
etisserant@0: 	fprintf(f, "this file must be include only once in the project\n");
etisserant@0: 	fprintf(f, "*/\n");
etisserant@0: 	fprintf(f, "\n");
etisserant@0: 	fprintf(f, "/* clock speed in MHz */\n");
etisserant@0: 	fprintf(f, "#define CAN_CONTROLER_CLOCK_SPEED %.3lf\n", frequency);
etisserant@0: 	fprintf(f, "#define CAN_CONTROLER_PHASE_SHIFT_TOLERANCE %d\n", sjw);
etisserant@0: 
etisserant@0: 	sjw = sjw << 6;
etisserant@0: 
etisserant@0: 	fprintf(f, "\n");
etisserant@0: 	fprintf(f, "static int can_baudrate_registers[9][3] =\n");
etisserant@0: 	fprintf(f, "{  /* BTR0    BTR1 */\n");
etisserant@0: 
etisserant@0: 	for(i=0; i<MAX_BIT_TIMING; i++)
etisserant@0: 	{
etisserant@0: 		if (array[2*i] == 0  && array[2*i+1] == 0)
etisserant@0: 			fprintf(f, "    {0, 0x00, 0x00}, /* %4d kbits/s -- out of range*/\n", 
etisserant@0: 				table_bit_timing_settings[i][0]);
etisserant@0: 		else
etisserant@0: 			fprintf(f, "    {1, 0x%02x, 0x%02x}, /* %4d kbits/s */\n", 
etisserant@0: 				sjw|array[2*i], array[2*i+1],
etisserant@0: 				table_bit_timing_settings[i][0]);
etisserant@0: 	}
etisserant@0: 
etisserant@0: 	fprintf(f, "};\n");
etisserant@0: 	fprintf(f, "\n");
etisserant@0: 	fprintf(f, "#endif\n\n");
etisserant@0: 
etisserant@0: 	fclose(f);
etisserant@0: }
etisserant@0: 
etisserant@0: 
etisserant@0: int main(int argc, char *argv[])
etisserant@0: {	
etisserant@0: 	if (argc == 3)
etisserant@0: 		print_header(atof(argv[1]), atoi(argv[2]));
etisserant@0: 	else
etisserant@0: 		printf("usage: %s clock_in_Mhz error_rate_in_percent\n", argv[0]);
etisserant@0: }