Wow. That must have been deep back in the archives! I had always considered the HD44780
to be the grand pappy of character LCD controllers, you found grand pappy's uncle!
The only way I can think of to proceed would be to make a translator. If you started with something like an Adafruit Feather M0
. it is small enough you could probably fit it in the system mechanically, and fast/powerful enough to emulate the old display without any code heroics.
Hook one set of pins to the host board's LCD interface that would normally connect to the Epson LCD. Connect another set to a modern LCD that has the same physical size.
Connect the host's /WR pin to an interrupt on the M0. When /WR falls, read all other pins and interpret what command was just sent. Use that information to maintain an array of characters (2x16 or 2x20) representing what should e on the LCD. Any time that image changes, push the array out to the modern LCD.
You would also want to check the /RD line with a scope in normal operation, my guess is that /RD is never used so you would not have to implement it.
If you got really fancy, you could run the VR lines into an ADC and use those to control the contrast (Vo) pins on the modern LCD.
Then post it on Hack-A-Day
Sorry we do not have a better solution than that. Of course, if you needed thousands of these, we could build it up as a semi-custom