UMD

Project UMD
Under Monitor Display hacks
Status	In progress
Contact	Eightdot, Sebastius
Last Update	2016-11-13

Introduction

todo

on Host

stty -F /dev/ttyUSB0 115200

C code:

./test CD 01 05 ff `echo Hoi RevSpace | perl -nle'print join " ", unpack("H*", $_) =~ /(..)/g'`  > /dev/ttyUSB0

Perl code:

perl test.pl "Hoi RevSpace" > /dev/ttyUSB0

C code

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

unsigned short crctbl[]={
	0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
	0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
	0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
	0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
	0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
	0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
	0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
	0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
	0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
	0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
	0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
	0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
	0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
	0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
	0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
	0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
	0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
	0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
	0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
	0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
	0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
	0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
	0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
	0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
	0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
	0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
	0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
	0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
	0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
	0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
	0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
	0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
};

unsigned short docrc(unsigned short crci,unsigned char data)
{
	unsigned short idx,crc;
	crc=crci;
	idx = (crc ^ data) & 0xff;
	crc >>=8;
	crc ^= crctbl[idx];
	return crc;	
}



int main(int argc, char ** argv)
{
	int i,len=1;
	unsigned char buffer[512];
	unsigned char tmp;
	unsigned short crc=0xffff;
	buffer[0]=0xfe;
	for (i=1;i<argc;i++)
	{
		tmp=strtol(argv[i],NULL,16);
		crc=docrc(crc,tmp);
		if((tmp==0xff) || (tmp==0xfe) || (tmp==0xfd))
		{
			buffer[len++]=0xfd;
			tmp ^= 0x20;
		}
		buffer[len++]=tmp;
		//printf("%04x\n",crc);
	}
	tmp=crc ^ 0xff;
	if((tmp==0xff) || (tmp==0xfe) || (tmp==0xfd))
	{
		buffer[len++]=0xfd;
		tmp ^= 0x20;
	}
	buffer[len++]=tmp;
	tmp=(crc>>8) ^ 0xff;
	if((tmp==0xff) || (tmp==0xfe) || (tmp==0xfd))
	{
		buffer[len++]=0xfd;
		tmp ^= 0x20;
	}
	buffer[len++]=tmp;
	buffer[len++]=0xff;
	for(i=0;i<len;i++)
	{
		//printf("%02x ",buffer[i]);
		printf("%c",buffer[i]);
	}
	//printf("\n");
	crc=docrc(crc,crc ^ 0xff);
	//printf("%04x\n",crc);
	crc=docrc(crc,tmp);
	//printf("%04x\n",crc);
	return 0;
}

Equivalente Perlcode

#!/usr/bin/perl -w
use strict;
use Digest::CRC;

my $crc = Digest::CRC->new(
    width => 16, init => 0xffff,
    xorout => 0, refout => 1, poly => 0x1021, refin => 1, cont => 1
);

my $text = shift;

my $command = "\xcd\x01\x05\xff$text";
$crc->add($command);

my $checksum = "\xff\xff" ^ pack "v", $crc->digest;

$command .= $checksum;
$command =~ s/([\xfd-\xff])/"\xfd" . ($1 ^ "\x20")/ge;

my $packet = "\xfe$command\xff";
print $packet;