Memory Mapped LED - Phase 2!

If you remember a while back when I was doing my Plus4 LCD screen, I spent a lot of time simply mapping a BYTE into the Plus4 memory space(Blog HERE). Well, I finally found something that will assemble source files for my GAL's, so I decided to play with trying to get my RAM expansion idea working. The first thing I had to do yet again, was map a byte into memory, but this time it was FAR easier!

You can see from the pictures that theres a LOT less, and even less soldering! Fantastic! This is the one bit that really puts me off doing any hardware stuff, I really dont like soldering that much. Well, with these GAL's, a whole array of chips have collapsed into 1! Not only that, but theres a lot more pins available, so I can add even more functions, and reprogram it as need be! Brilliant!

I did know what they were able to do before, but I was unable to make them until today when I found a program called fgal.exe, which is basically a GAL assembler. Now I can simply assemble this line...

     WR = A15* A14* A13* A12* A11* A10* A9* /A8* PH2* /RW

.... and I've done all the work of those 4 other chips! Great stuff. Now I can actually try out the external 256k RAM pack idea I had, where I dont modify anything internally... could be neat if it works!

One thing that would be very cool, is a pass through connecter, but from what i hear, you dont get these edge connectors any more... pitty.

I'm thinking of saving up for a milling machine so I can cut/make my own PCB's easily, this would mean that once I design it, I can (more or less) press a button and get a prototype board out! These are pretty expensive, but I think it'll be great fun so I hope to have one by the Christmas holidays...I hope.