I own a device that has faulty 256 x 64 dot matrix display (flat cable damage + some bug infestation). After a disassembly I discovered that display is connected via 20-pin connect (soldered pins).
I connected the logic analyzer and got the signals from 12 pins. Every four seconds signal from picture 1 is appearing with the new data.
I am trying to compare it with 8080 and 6800 but I cannot notice the pattern.
Picture - zoom level 1: 
Picture - zoom level 2 - beginning of the signal: 
- Signals on 1,2,3,4,8,9,10,11 look like data (8-bit)
I would like to discover which protocol this could be but it is kind of confusing to me. How to be sure which one is it?
Could you recommend any display controller simulator (that uses popular parallel protocols) that could run on the computer (I would like to test the data and pixel output before soldering the real replacement device?
What could be the reason behind the frequency change (pic1 vs pic2)?
I've used DSView with DS Logic Analyzer. I posted the data from this measuring to the github (can be opened with DSView tool):
Additional information
- Display manufacturer: Truly
- Model: mgg2257b2-e
- Display driver NOT present at PCB (has two COG present)
- MCU: Motorola's MC9S08GB60A
Update
After a bit of investigation I discovered that this is a multiplexed LCD direct drive.
Two drivers are COG type and those are directly connected to MCU (HCS08) via 13 pins (I traced the connector pins via resistors to cogs). COGs are also sharing 11 pins. This device is at least 10 years old and it seems that manufacturer has selected the cheapest way at that time to create a GUI (without controllers). I don't know should I close this question and ask another question or edit it completely.
I would definitely like to learn more about this approach so maybe this question could be useful for others as well.
Idea is to get the info about the COG. Not sure could this be custom made COG. I hope it is not.