Shop OBEX P1 Docs P2 Docs Learn Events
Console Emulation - Page 68 — Parallax Forums

Console Emulation

1626364656668»

Comments

  • RaymanRayman Posts: 14,721
    edited 2024-11-22 21:58

    Changed this line in NeoVGA and appear to have changed clock freq to 350 MHz:

    VIDEO_CLKFREQ = 350_000_000 'MASTER_CLK*CLK_MULTIPLIER

    Monitor says 61.4 Hz refresh
    Gone a bit with no errors. Think this means that MisoYume should work.

    Hmm. Won't do 355 MHz. Not 100% sure if it's the monitor or the P2 giving up...

  • @Rayman Yea you can change the frequency like that, but the video will go faster. i guess most monitors should sync up to 70Hz, so that should be fine. Your monitor should say something like "OUT OF RANGE" if it isn't taking the video signal.

    With those dummy cogs running, it's way more stressful than NeoYume. Try it on one of those older boards. They just can't handle it at all. Also, the memory test is exacting. A single bit error anywhere will trip it, whereas the actual emulator can often shake it off.

  • RaymanRayman Posts: 14,721

    Tested again today and did eventually fail (no fan).
    Board was pretty warm though.
    Think fan would fix it...

    2016 x 1512 - 679K
  • RaymanRayman Posts: 14,721

    Tried with Vdd = 1.9 V. Works at 338 MHz, but not 350 MHz...

    MisoYume runs for a few seconds at Vdd=1.9, but then crashes...

  • New finding: Running MXX board off a 12V wall brick results in VBUS = 4.99V. A lot better.
    Probably more interesting would be how this affects the RAM VIO rail.

    Still need to measure a bunch of different boards and power methods.

  • Despite the better VBUS voltage, the overall stability seems to be reduced running from the 12V supply. Very strange failure modes.

  • To illustrate:

    Like what?

  • roglohrogloh Posts: 5,833

    Might be a noiser power supply brick somehow coupling through to the VIO rails of the P2 or other PSRAM signals. You could scope it to see different amounts of noise on the voltage rails with different supplies, although it's not that that accurate and hard to find transients unless it's grossly different from other supplies or you have a good high bandwidth scope.

  • RaymanRayman Posts: 14,721
    edited 2024-11-27 22:04

    This makes me like the idea USB-C power more and more...

    Is the 12V used for anything there? If needed, guess need a USB-C PD chip for that...

  • @rogloh said:
    Might be a noiser power supply brick somehow coupling through to the VIO rails of the P2 or other PSRAM signals. You could scope it to see different amounts of noise on the voltage rails with different supplies, although it's not that that accurate and hard to find transients unless it's grossly different from other supplies or you have a good high bandwidth scope.

    I think this is the core giving out though, notice how there's ERRs and OKs outside of the intended grid. I've also had hard crashes and other screen corruptions happen.

  • To belabour the point:

  • Back to USB input and suddenly it works again

  • Or maybe not

    I feel like I may have cooked the board too much.

  • evanhevanh Posts: 16,016

    This is the point where I would wire up the oscilloscope to get some sanity back.

Sign In or Register to comment.