/* This code is Copyright 1996 Tommy Johnson
** 
** Unix implementation of the Timex Datalink protocol using an LED on a
** serial port.  (see datalink.ps)
**
** See http://csgrad.cs.vt.edu/~tjohnson/ for more info.
**
** Timex and Timex DataLink are registered trademarks of the Timex Corp.
** This was developed independantly of Timex.  Timex does not support it,
** DO NOT ask Timex questions about it.
**
** Permission is hereby granted to copy, reproduce, redistribute or otherwise
** use this software as long as: there is no monetary profit gained
** specifically from the use or reproduction of this software, it is not
** sold, rented, traded or otherwise marketed, and this copyright notice is
** included prominently in any copy made.
**
** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
** IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
** FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. ANY USE OF THIS
** SOFTWARE IS AT THE USER'S OWN RISK. 
**
*/

#include<stdio.h>
#include<fcntl.h>
#include<stdlib.h>
#include<termios.h>

#include<sys/time.h>
#include<sys/resource.h>

#define PORT "/dev/ttyd1"

void sendbyte(int fil, unsigned char dat)
#define ZERO "\0xff\0\0\0\0\0"
#define ONE "\0\0\0\0\0\0"
#define LEN 6
{
	static int frame=0;
	char buff[1024];
	int c=0;
	int i;
	memcpy(&buff[c],ZERO,LEN);
	c+=LEN;
	for(i=0;i<8;i++)
	{
		memcpy(&buff[c],(dat&1)?ONE:ZERO,LEN);
		c+=LEN-(i&1);   /* CHEESY! the baud rate dosn't quite  */
				/* match, so alternate too long and too */
				/* short.    */
		dat>>=1;        /* and... IT WORKS...  (shudder)       */
	}
	for(i=0;i<(frame?12:4);i++)
	{
		memcpy(&buff[c],ONE,LEN);
		c+=LEN;
	}
	frame=!frame;   /* a frame is 2 words, which would have been on */
			/* a single CRT frame (different inter-word pause) */

	write(fil,buff,c);
}

/* For pauses between packets: */
void pause(int fil, int count)
{
	char buff[8192];
	int i,c;
	
	c=0;
	for(i=0;i<(count*LEN);i++)
		buff[c++]=0x0;
	write(fil,buff,c);
}
		
#undef ZERO
#undef ONE
#undef LEN

main(int argc, char *argv[])
{
	int port;
	int data;
	struct termios old,new;
	int c,i,j,len,plen;
	char buff[4096];
	char fil[1024];
	char device[1024];

	setpriority(PRIO_PROCESS,0,-20);  /* pauses will screwup the timing */

	strcpy(fil,"DEBUGOUTPUT");
	strcpy(device,PORT);             /* defaults */

#ifdef OTHERCMDLINE
	while((c=getopt(argc,argv,"h?d:f:"))!=-1)
	{
		switch(c)
		{
			case 'h':
			case '?':
				fprintf(stderr,"%s [-d device] [-f file]\nTransmitt a file to a Timex Datalink watch useing an LED on a serial\nport.  Timex does not support this product, DO NOT ask them questions about\nit.  See http://csgrad.cs.vt.edu/~tjohnson/ for more info.\n",argv[0]);
				exit(0);
				break;
			case 'd':
				strcpy(device,optarg);
				break;
			case 'f':
				strcpy(fil,optarg);
				break;
		}
	}
#else
	if (argc==2)
		strcpy(fil,argv[1]);
	else
		{
			fprintf(stderr,"%s file\nTransmitt a file to a Timex Datalink watch useing an LED on a serial\nport.  Timex does not support this product, DO NOT ask them questions about\nit.  See http://csgrad.cs.vt.edu/~tjohnson/ for more info.\n",argv[0]);
		exit(0);
		}
#endif

	data=open(fil,O_RDONLY);
	if (!data)
	{
		perror("open datafile failed:");
		exit(1);
	}
	len=read(data,buff,1024);
	close(data);
	printf("data length:%d\n",len);

	port=open(device,O_RDWR);
	if (port<0)
	{
		perror("open of device failed:");
		exit(1);
	}
	
	if (tcgetattr(port,&old)<0)
	{
		perror("tcgetattr failed:");
		exit(1);
	}
	new=old;
	cfsetspeed(&new,B115200);
	if (tcsetattr(port,TCSANOW,&new)<0)
	{
		perror("tcsetattr failed:");
		exit(1);
	}
#if 0
	while(1)
		pause(port,20);   /* used for hardware debugging */
#endif
	printf("sync1\n");
	for(i=0;i<500;i++)
	{
		sendbyte(port,0x55);
		if (!(i%100))
			printf("%d\n",5-(i/100));
	}
	for(i=0;i<50;i++)
		sendbyte(port,0xAA);
	printf("sync2\n");
	i=0;
	do
	{
		plen=buff[i];
		printf("%d\n",plen);
		for(j=0;j<plen;j++)
			sendbyte(port,buff[i++]);
		if (plen&1)
			sendbyte(port,0);
		pause(port,240);
	} while (i<len);

	pause(port,240);
	tcsetattr(port,TCSADRAIN,&new);
	sleep(1);
	close(port);
}