I got two old LCD modules without complete datasheets, Epson EA-Y16025 and IEE 3802-03-032. I tried to search some information on these from the Internet, but I found people only asking questions and having the same problems. So I had to use trial-and-error method to make the modules work.
I had these documents about the modules:There was enough information to make the IEE display operate while the information on the Epson module being inadequate. I found that the Epson EA-Y and EA-X series use the same controller, SED1300.
Some EA-X specs can be found here:I tested the modules using my own PC-ISA I/O card. The data and control signals of these old modules operate the same way as in newer modules, but the EA-Y required some weird additional signals (FG, ENB, VR1 and VR2). After some research, I drew this schematic and made a prototype:
FG pin is Frame Ground and it can be left floating.
The I/O board specs and the source code of the software I was using is found here (PC assembly):Unfortunately, the SW comments are in Finnish only. However, the data and control pin connections to the I/O card can be found there. Both modules accept quite similar commands as the new industry-standard ones. The test sofware sends ASCII characters to the display until the esc button is pressed.
