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View Full Version : [queued] ROM reader with teensy 3.5



Luz
08-23-2018, 09:23 PM
Hi guys,

I have built a reader for old ROMs and uploaded the code here: https://github.com/Luz/sega-rom-reader

The teensy 3.5 was used because its inputs are 5V tolerant. For the outputs, the 3.3V are also compatible with the TTL logic, since 2.4V is accepted as high.

Here are some pictures:
https://raw.githubusercontent.com/Luz/sega-rom-reader/master/pics/pic1.jpg
https://raw.githubusercontent.com/Luz/sega-rom-reader/master/pics/pic2.jpg
https://raw.githubusercontent.com/Luz/sega-rom-reader/master/pics/pic3.jpg
https://raw.githubusercontent.com/Luz/sega-rom-reader/master/pics/pic4.jpg

The "wire wrap"-technique was used because I love it.

Frank B
10-27-2018, 10:34 PM
Wow... impressive.I like such retro projects very much!
And a lot of work to do by hand!

Nowadays the Chinese are so cheap and fast (and that with top quality) that I don't do that to myself anymore. Usually the circuit board is already shipped the next day.
Besides, you usually get 10 boards, which I often give away :)

Luz
10-29-2018, 05:19 PM
Yes, I have also made like 20-30 different pcb's, but I really like wire wrapping, and I wanted to have it faster than chinese :D
Also I still have stuff to add to that project, so the pcb will still change a bit. Maybe I'll make a real pcb later :)

Robin
02-21-2019, 05:45 PM
I'm not all that familiar with most game consoles. What do you do with the ROMs once you've read them?

Theremingenieur
02-21-2019, 08:35 PM
Once read, one might either use the code in emulators, or simply duplicate them to build clones. The high school is analyzing and modifying the code to add cheats.

Frank B
02-21-2019, 08:52 PM
For most of the old ROMS, so-called "ROM-LISTINGS" with dis-assembled code are available on internet. Nevertheless, it's a great project, esp. if you have a rare ROM version, or if it is not available for download.
For C64, they used several versions, and even 3rd-party ROMs where available (for $$$). For the disk-drives (they had a CPU, too) were "turbo"-versions with higher transfer-speeds available. C64-Disk-drives were very slow that time.. mostly caused by a silicon-bug that needed a software-workaround for one of the c64-chips, so the originally commodore- intended hardware-supported transfers were not possible. Modern emulators try to mimic these bugs... (and for the sound-chip are VERY exact emulators available that emulate every little detail because many sound-effects relied on not-documented special clock-cycle dependend behaviour - the "reSID" is such a emulation)
(Yes, even in the "good old times" there were silicon-bugs... :)
Sorry for off-topic..

Luz
02-23-2019, 08:32 AM
I'm not all that familiar with most game consoles. What do you do with the ROMs once you've read them?
The goal was to read the roms that I've programmed, but the programmer isn't finished yet.
When reading/writing works, then comes the hardest part... setting up a toolchain for c -> asm