The code is written such that the EEPROM is only read at startup, and only written to when you change buttonmaps. I believe the EEPROM is rated for at least 100,000 read/write cycles so I doubt it would be an issue.
Cool, let me know if you have any issues. I think I can compile a HEX file, but I think the fuse bytes have to be set manually if you burn a hex instead of using the Arduino IDE. I'm not sure what needs to be set in that case. At the very least the 8mhz internal oscillator has to be enabled for it to work on my PCB.
Hey, this is cool that you are porting your code to the same layout. I don't understand how R1 and R2 are wired on your board though.The timing on the Saturn's select lines is odd. The period of time that each select line is held high or low is not consistent. I don't have exact timings recorded anywhere, and I don't really have time to set up a test rig for it right now, but as I recall it cycles between 3 of the 4 select states very quickly, and holds on the last select state for a longer period of time. I assume that the gap in the select pattern is meant to accommodate more advanced controller protocols like the 3d pad, but I don't know much about those. I suspect that the chip being used by the Retro Bit controller is an off the shelf microcontroller of some sort, and is probably sensitive to the select timing of the Saturn.
I ran into a similar problem trying to get the Brook Retro Board working with my own Saturn to DB-15 adapter code, and adding the gap in the select timing fixed the problem. I can confirm that the Retro Bit controller does work with my adapter code also.
@twistedsymphony Perhaps try adding delay to the select pulses in your code. If I remember correctly the Saturn cycles through all of the select lines at around 90Hz.
With all of that said, I went ahead grafted an ATMEGAXX8 microcontroller onto @Frank_fjs's superior PCB layout that will work with my Arduino based Saturn pad demuxing code.
The Oshpark link contains the BOM.
Here is a link to my Github repository for the Arduino code.
I'm not sure what you mean. Are you talking about resistors R1 and R2? If so, they are in parallel and are only there for current limiting in case of a short circuit in the controller cable.
If you are planning on running the code on an Uno, you can just upload the sketch directly to the Uno through serial. If you are going to use either of my custom PCB designs you will need to us an ISP programmer to burn the code to the chip, and set it to use the internal 8mhz oscillator. You can use a USBASP or you can use the "Arduino as ISP" sketch on an Uno. You will want to install "Minicore" in your boards manager to make it easy to set everything up properly for your chip.
Unfortunately I don't have a top3000 so I don't know if Atmegas are supported or how to set up the programmer to write the correct fuse bytes. Maybe someone else has experience with this?
I can open the Top3000 and search for the Atmega chip , and see if these are supported...
