Recent content by epooch

Those cheap $10 USB logic analyzers are very useful for troubleshooting. They work great with sigrok PulseView or Saleae Logic. Great way to get started and identify what you need for long term.

Find somebody else that wants to do them: sell it, trade it, or pass it along. Better somebody who really enjoys it and wants to do it right than to half-ass it just to get it done. I have spent way too much time un-doing somebody else's "chores" that they clearly weren't interested in enough to...

HD44780 character LCDs on the parallel port were my introduction to programming for hardware.

Shoot, on second look, I was wrong about that. there are actually 9 pull-ups. But, I am still thinking that where the data bits go looks similar to the SSC switch layout.

Note that the switches are just the default settings and your communications client should be able to change the settings, especially if the firmware is SSC compatible. It appears that there are only 7 pull-up resistors per bank of switches, so you are right back in line with the SSC switches...

My now working Disk ][ drive disagrees with you. Even though the Shugart SA-400 adjustment instructions indicate fluorescent, I don't think I could get a CFL to work. Maybe how the new bulbs are made? Incandescent bulb in a dark room in a plug-in lamp close to the drive worked for me. I am sure...

You can also use an incandescent lamp and the "stroboscopic" timing marks on the bottom of the Disk ][ drive spindle to get the speed properly tuned. I was able to get a drive that would not boot working that way. It works!

I saw this at their shop the the other day. it is in very nice condition. I don't think they have anything else though.

I am not sure if I should be happy that you have a working EVK-300, or sad that you still can't assemble the board. :LOL: Nice find! I don't think I have ever seen a white ceramic 6800 before.

Replacing with 4164 DRAM is pretty trivial, and addressing 48k of them (replacing all 3 rows with one row of 4164) just needs a few signals from around the motherboard, and a 74ls153 on an external board instead of the the 74LS257 in J1. Also, you need to use "128cycle/2ms refresh" (like...

I definitely appreciate the variety of these EXORbus boards. From super simple, to :

Nice score! Great price too, especially considering what trainers are fetching lately. That MEK 6800 D1 is so simple, no bus buffers or clock crystal?! It would be a fun SBC to build from scratch.

Thank you all for the follow-up. I did a fair bit of work reverse engineering the MIKUL 6809-5 and 6218 on my site. The ones I bought boot right up together and the firmware was usable with the addition of a cheap keypad. The MIKUL 6218 in particular makes a great platform for a high capacity...

I’m adding JED files to my GitHub repo!😅

I just checked a repository I have and sure enough, I did not include the JED file, only the equations. Adding it feels like including a binary with the source code. It is completely useless for me to edit or understand. The JED file is just an intermediate file for my purposes. I guess I don't...