TomNisbet
commented
2 years ago Adding another shift register to support 22 address lines would be a trivial extension. In fact, you could use the output from one of the current shift registers to clock data into the new one and there would be no need for any additional connections to the Arduino. You'd just need to extend the SetAddress code to clock additional bits into the high register pair.
The 32 data lines would be a bit more difficult because they are bidirectional. I would use something like an Arduino Mega 2560 to get additional pins and then drive all of the data pins directly. This would be much simpler than trying to design some sort of multiplexed hardware interface that extends the 8 arduino pins to 32.
The TommyPROM code is very modular and could be adapted to do what you need. In fact, I am working on code right now to program some Atmel NOR flash. One adaptation for your project would be to interpret the data as 32 bits instead of 8. That's probably the most difficult part.
If you want to send me more details about your ROM board, I may be able to offer some additional insights, It sounds like an interesting project!
Hi Tommy,
I'm trying to build a reader/writer for a 128mbit ROM board that uses a 72 pin SIMM based pinout (essentially, it's two SOP44 64mbit NOR Flash chips in parallel, so it's got 32 data lines and 22 address lines). This is quite a bit bigger than an EEPROM! But I was hoping that since it's fairly simple in scope, that the TommyPROM concept would work with more shift registers.
What I wanted to know, as a fairly green electronics person to someone who is a little more experienced, am I barking up the wrong tree here, or do you think this is possible?
Thanks, AJ.