I recognize that I'm bringing this thread back from the dead - but I'm working on the same board and have the same questions. I've been hunting for a suitable COG replacement, and have realized that I may not be able to find one. I would be willing to have one produced, but I need some assistance in determining the communication protocol of the LCD. Could anyone guide me in this process? I have some basic scripting skills and would gladly purchase a Raspberry Pi or other materials to complete this project.

Mod: Created new thread.
Link to old:
https://forum.allaboutcircuits.com/...find-suitable-replacement.163128/post-1432210

 

Probably the LCD display is not available at all except as a part of a used device. And that is unlikely. But it might be possible to decode the drive to that device and use a little processor module to convert it to code to drive a current production display. More likely to succeed.

 

Probably the LCD display is not available at all except as a part of a used device. And that is unlikely. But it might be possible to decode the drive to that device and use a little processor module to convert it to code to drive a current production display. More likely to succeed.

That's my current plan. There are two microcontrollers on the board. One is a PIC16F73-I/SO and the other is a AT93C46-10SI-2.7. I have a version of the board that does not have an LCD screen and is controlled by an LED instead, and it does not have the Atmel chip. I believe I can copy the information from both chips with the right equipment, and I'm hoping this will result in being able to use a currently available display for the old boards. I would love to be able to utilize a character OLED. The original LCD appears to be a simple 8x2 COG character LCD.

I have multiples of these boards and can perform SMD and through-hole solder work.

If anyone can provide me with some guidance in this project, I would much appreciate it!

 

I'm not going to say it's not possible, but there are configuration bits that can be set to prevent anyone from reading the code from microcontrollers. Without the program the EEPROM data is probably useless.

 

I'm not going to say it's not possible, but there are configuration bits that can be set to prevent anyone from reading the code from microcontrollers. Without the program the EEPROM data is probably useless.

I appreciate the input. I'd like to at least try reading the data before calling it a loss. I've always wanted to understand how to work with these microcontrollers, this will be my first foray into it.

 

Since you have a PI on hand I would suggest checking out https://wiki.kewl.org/dokuwiki/projects:pickle

It won't help with the 16F73 as far as I can tell without some extra work, but for many PICs it does work good without having to buy a programmer. I didn't dig around for the programming spec, but I'm going to guess the 16F73 is going to need in excess of 12 or 13 volts on the MCLR pin to get it to enter programing mode.