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A2600 clone, 6591 chip pinout

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I found an old Atari 2600 console clone in my basement.

Seems to be broken, some parts are missing, but the chips are all OK (CPU and ROM, I guess).

Therefore I'm wondering about reusing these parts somehow on a breadboard or something.

But in order to do this, I need some information on these chips and their pinouts, maybe some datasheets or schematics.

The chips are labeled as follows:





DIP-48 (two rows of 24 pins each, 48 in total)

Seems to be the CPU.



DIP-32 (two rows of 16 pins each, 32 in total)

Seems to be the ROM.

As far as I know, there was no cartridge slot, so the games must be stored on that ROM.


There's an empty place on the PCB for another DIP-28 chip, the silkscreen label says "IC3 512K MASK ROM", but there is no chip there and it seems that it has never been.




Just four 2-input NAND gates.




Motorola chip, 7-stage ripple counter, I guess for clock division or something, since it is near the quartz resonator.


The resonator is:



(which I guess is its frequency in MHz)


I see no separate TV circuit/chip, so I guess the TV signal is generated on the main CPU somehow.

Could it be that the CPU has a TV signal generator integrated in it?


I can post some photos of the PCB if needed. But I hope the labels on the chips will be enough for the experts to identify them.


Can anyone help me with identifying the chips and supply some descriptions of their pinouts?

Perhaps some more detailed datasheets?



I also found an old Atari 65 XE motherboard.

Unfortunately it's broken in half :P so the chips in the middle of the board are broken as well ;/

But other chips on the edges of the board are OK, so I'll try to reuse them as well.

But I'll describe that in a separate thread later.

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Strange - full blown 6502 is only 40 pins, 6507 as per 2600 is only 28. Possibly the extra 20 pins means it has the bulk of the system on one chip (6507, TIA, RIOT)


You could probably work out the address/data by getting a datasheet for the ROM and work from that.

If the other parts of the system are also on the large IC then you might be able to deduce other pins like audio, video etc. Stuff like switch and Pot lines should be fairly easy.

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Hi, I've got a clone built around pretty much the same components.


The 6591 is a VCS-on-a-chip which outputs nice and clean S-video via 2 lines: Chroma and Luma only unlike original Atari design where Luma was being mixed from sub-signals/resistors' mix (Lum0 thru Lum3 it was?). Amplification is still required tho, but you can just use any of the video drivers described in Famicom AV modifications, etc.

It plays all regular games and demos perfectly (no weird issues like certain TIA revisions) and cooperates with Harmony as expected from the original system.

Only drawback is that it lacks analogue inputs, so no paddle games. Great for a portable Demo station tho, the motherboard should have a silkscreen print of the cartridge port placement, even if the cartridge port was missing.


There's a nice clean schematic of similar clone on mr. Sobola's page.:


It does have some errors with the pins' numbering tho!


A bit dirtier schematic (MegaBoy, actually based on 6592 - same thing anyway), was published in an article about M&M' box tiny Atari.:



Good if you just need something minimalistic.


P.S. MC14024BCP is for counting the resets and incrementing the ROM bank number based on this. That's how the games are selected.

Edited by Mef

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