3 comments on “Project:65 – Running a program

  1. Jeez, the hobbyists of today know so little compared with the ‘good old days’ when 6502’s, 8080’s and 2650s were the thing.

  2. I’m in the process of wiring-up a simplified EPROM/EEPROM burner/writer, but using an Arduino MEGA-2650.. The reason for the bigger Arduino, is the additional address lines on the older EPROMs, and larger EEPROMs (looking at a 29C010 & 29C020 sitting on bench, pulled from two old motherboards), thus not requiring the I2C communications.. One thing I’m looking at, is trying to wire-in a Ethernet/SD-Card shield, to handle transfers of the data. (the data from the computer is fed to the Arduino, stored on the SD card, then burned to the device.. There is a Blog article from MAKE: magazine, by Matt Richardson, about someone who wired-up a EPROM reader, using just the MEGA as the platform. I would imagine wiring-up a relay to one additional digital line to handle “-PGM” (or -WE), switching in/out a +5, +12, +21V programming voltage. I have a couple of old burners, BUT…. one, used an old S-100 card from an old Compupro 8/16, (which is long since gone), and quite a few of the personality modules are gone.. The other, was an old 8-bit ISA card for an IBM-XT type computer, but I can’t find the disks.. Matt’s blog entry, is at http://blog.makezine.com/2012/07/08/how-to-read-a-rom/ , and the article, is at http://www.nycresistor.com/2012/07/07/stick-a-straw-in-its-brain-and-suck-how-to-read-a-rom/ .. One note, the arduino code used to read the EPROMS, assigned the variable A0 to the address pins (from Digital pin 26 up, dependant on the # of bytes).. Except…. Guess what it was seeing as an error in the code? A0 stands for Analog 0.. I changed all of the A0’s in the code to AD0, so it would work.. Building a +21V supply.. Now, there’s the fun!

  3. Hi! I’ve been wiring up my 8-bit computer following a very nice and complete guide I’ve found. By now i’ve been working with three chips: 6522 (VIA for the I/O), 2865 EEPROM and, of course, the mistifying 6502 microprocessor. I’ve wired up everything together and finally powered it on. Unfortunately I didn’t get the results I was wondering. By the way, I programmed (or at least I think I did) my 2865 “by hand”, wiring the address pins and the data pins according to the program I wanted to “upload” for testing purposes.

    For the clock signal generator (square signal generator) I’m using a small circuit made up by a 7404, some resistors and a 2MHz crystal (this crystal is not the one we can commonly find in motherboards that is made by quartz crystal inside a small metal canister; it’s more a plastic capacitor like).

    So, regarding this, what can you recommend me about the square signal generator and the 2865 programming by hand?

    Thanks in advance and let me tell you that I’m happy to find more 6502’s enthusiasts these days.

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