PIC-LCD-PC interfase

[lw1ecp]

Hi!. I built this frequency counter with a PIC:
www.qsl.net/om3cph/counter/lcd/contribs/images/schema1.gif
I would like to log the readings on my PC. It has a parallel port, I thought about connecting it to the 7 lines between the PIC and the LCD. Looking at the waveforms there, shorter pulses are 1us wide. The PIC takes 10 measurements per second. The interfase is 4 bit, and uses the R/W line.
Did anyone do anything similar?. I wouldn't care having to use x86 ASM and/or booting the PC in DOS to avoid colliding with Windows administration.
Thank you!.
Daniel LW1ECP

 

[paulfjujo]

hello,

To catch the information send to the LCD is a hard way.. because mode 4bits , but not impossible..
You can test in Win Xp environment to use VB6 + inpout32.dll
see **broken link removed**
but i don't know if the speed will be enough...
because using a dll is not the fastest way.. best is 100% asm !!!
so if you can use DOS stand alone..

i have also old application as "SCOPES" , ADC acquisition trought LPT port
writen in Turbo C2 , and some asm subroutines.
works only with OS less or equal to Win98


Can you change the program inside the PIC ( PIC16F or PIC16C OTP).
If yes , maybe you have some rom space to add an UART output on RA1
put R/W LCD tozero volt , so RA1 is free as an Output..
to handle RS232 bit bang is not compliated for output only.

you need to do some reverse engineering
to intercept the Init part to add UART config
and the end of main loop of programm
to insert the UART output.

or rewrite all the code ...

 

[lw1ecp]

paulfjujo, many thanks for your hints!. I also fear VB would not be fast enough, what seems to be the strobe is 1us-wide. And even if it could do the job, I would still have to know how to differentiate the read from the write operations, and command from the data operations. Working with 4 bits is no problem, I could save the raw data and after I have the file I could do the manipulations to re-create the ASCII characters. I do have the PIC source code, I have done something in PIC ASM in the past, but at present I am so busy that I aimed at finding a ready-made solution. After all, wouldn't it be of help to everyone using a LCD module, be it a frequency counter, an ADC, etc.? Someone must have devised something like this. I'll keep searching a little more, wish me good luck!