Nintendo 8-Bit Homebrew Clone Console

Description

BaffaNES is a NES clone that offers two sockets for 60 and 72 pin cartridges.

After "BaffAtari" project I aimed to create an 8-bit Nintendo clone. It's been a little over thirty years since I got my NES but I still play some games or show them as an example of game design from old games. Adaptations of classic Arcade games from the early 80's created for the NES are great and it's a great opportunity to play them.

For this project, I thought it would be best to create a board that could work standalone and then be connected to the "Baffa-2" through the expansion port. In the future, it may be possible to use it next to the computer to load games and possibly manipulate variables through a terminal program.

Unfortunately my documentation had some issues and this reflected in my first schematics and PCB version.

But, after some "patches" It works perfectly and now I can produce a final PCB version.

Project Logs

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Schematic Fully fixed... yey!
Augusto Baffa • 04/01/2023 at 15:16 • 0 comments

Finally, I could fix completely the board and It is now supporting nativelly two famiclone controllers. (Yes... now we have also a player 2!)
It's necessary order a new board using this new schematic version to add the sound amp fix, 72pin connection fix, PPU connection fix and both joystick connection fixes. But yes, the prototype is fully funcional. The only problem with it is the daugher protoboard that adds the sound amp circuit.
Issue 3: Famiclone Controlers have another pinout
Augusto Baffa • 03/20/2023 at 09:12 • 0 comments

... Yep... I forgot to tell that Famiclone Controllers have a different pinout from the schematics I based my project... but ok, I did an "adapter" and that's how I could test it...
My new board fixes all isues and adds an op-amp to amplify the sound output. I need to route all again...
Second Issue: Sound
Augusto Baffa • 03/12/2023 at 14:08 • 0 comments

The second issue I had was about the sound. Many PSG chips have an amplifier on it so I just need to adjust the impedance and attach to an amplified speaker or soundbox. I actually removed the RF signal and added a jack not knowing that a preamp was needed in the project. The result was having to improvise one and add it to my schematic. Now I can try to order another PCB with the final prototype results.
(Improvised preamp solution with op-amp TL071)
Issue 1 - Don't trust on old schematics and documentation
Augusto Baffa • 03/12/2023 at 14:02 • 0 comments

The first big problem was relying on old schematics. I consulted 2 versions of nintendo clones and the original famicom. There were serious differences in the PPU pinout. Even though I did my best, I couldn't get the bus right the first time, and had to do a major repair.
(The machine on this picture is the MSX version of Baffa-2. - ignore it :D )

Another problem is the fact that the original design used the BF494 transistor to oscillate the clock. It is very difficult to find a BF494 that works nowadays as many are rebranded or outside the original parameters. I made several purchases in different stores and tested several transistors from the BF494, BF494A series and I only managed to make it work when I took its brother BF495 and adapted it.

In practice, I found it best to use the 74LS04 to do the job, and it performed much better than the other tests.

The result is this:
Beautiful, isn't it?