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guruthree / mac-se-video-converter

Convert video from a Mac Plus/SE/Classic to a VESA VGA signal using a Raspberry Pi Pico
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Not quite working correctly with my Mac Plus. #5

Closed TimRustige closed 1 day ago

TimRustige commented 1 day ago

Hi, I built the circuit and it sort of works, but I have what looks like noise, see attached photo IMG_20241112_155520

Things I've tried to fix this issue: Tried a Pi Zero and a Pi Zero W Tried two different VGA screens - both the same, one is a really good multi sync Eizo L367 Tried a breadboard version and PCB I made - so different level shifter boards but same design Tried adding a diode to the 5v line from the Mac Plus that's powering the Pi Pico

I've not tried removing the level shifters yet. I can't see level shifters on the design at JCM-1.com or the links to the working examples?

I'm not using the Pimoroni board. I'm using the 3 resistors to a VGA port from a Pico Mac design here: https://github.com/evansm7/pico-mac

From what I read, different software values might be required for Mac Plus compared to SE?

TimRustige commented 1 day ago

also, a weird thing. If the floppy drive is connected, the system detects a floppy that needs formatting, even though the floppy drive is empty

TimRustige commented 1 day ago

Please ignore. Set the NOP to 22 , works great now. IMG_20241112_193158 ![Uploading IMG_20241112_193153.jpg…]()

guruthree commented 1 day ago

Great that you've got it working! I've updated the troubleshooting to link to this issue and included your description of 'noisy' to help anyone else track down the same problem.