SuperCIC for PIC10F322

Discussion of hardware and software development for Super NES and Super Famicom.

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poorstudenthobbyist
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Re: SuperCIC for PIC10F322

Post by poorstudenthobbyist » Tue Aug 25, 2020 10:33 pm

I believe LS series parts output 3.3V instead of 5V. Which certainly could have an effect on how much noise is radiated into the neighboring circuits. I'm slightly annoyed that I have to worry about conducted/radiated emissions - I thought I only had to deal with that kind of stuff at work, certainly not for SNES carts!

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Memblers
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Re: SuperCIC for PIC10F322

Post by Memblers » Wed Aug 26, 2020 7:33 pm

I mentioned this problem to kevtris, and he had some suggestions:

- check PIC config bits, and make sure power-up delay is turned off. Could be that the SNES and SNES Jr. have different reset lengths, and the PIC wasn't out of reset yet.

- use provided hex file rather than build from source. Microchip made changes to their assembler that affects the bankswitching macros, and if true, that could completely break the code timing.

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poorstudenthobbyist
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Re: SuperCIC for PIC10F322

Post by poorstudenthobbyist » Wed Aug 26, 2020 8:30 pm

Thanks for the tips!

I used the same 10F322 on two of my boards - one that uses the 27C322, one that doesn't. I didn't reprogram the 10F322 between swapping boards, and the non-27C322 board worked fine. I've been using the HEX file to program as well, not the .asm file - if the timing was broken by the assembler, wouldn't I have the problem on both boards?

lidnariq
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Re: SuperCIC for PIC10F322

Post by lidnariq » Wed Aug 26, 2020 10:18 pm

(Un)fortunately, 10F322 doesn't have any bankswitching, and I'd disabled the power-up timer in the in-band fuses.

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poorstudenthobbyist
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Re: SuperCIC for PIC10F322

Post by poorstudenthobbyist » Mon Sep 07, 2020 8:16 pm

Well, I have no idea what the problem is with this. I made two more board designs - both with 10F322s, both with very thick traces and power/ground planes overlapping the traces. No interference from any other line, except the trace coming from the reset pin on the cart connector has to overlap a few traces, but that's not switching at all so it shouldn't be a problem.

One design works, one doesn't. The one that doesn't is doing the same thing as what I described earlier. Even tried swapping the 10F322s between the working and non working board to see if it was a bad chip, but the problem follows the board. Both boards work with 12F629. So I don't know what the problem is. I guess I'll be abandoning my efforts to get the 10F322s working and stick with the 12F629, annoyingly.
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