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hoglet67 / RGBtoHDMI

Bare-metal Raspberry Pi project that provides pixel-perfect sampling of Retro Computer RGB/YUV video and conversion to HDMI
GNU General Public License v3.0
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Shorted/faulty CPLD? #374

Open axmandm opened 3 months ago

axmandm commented 3 months ago

I have an RGBtoHDMI purchased back in 2022. When I tried to use it yesterday, I only got a green output from my BBC Master.

I thought perhaps there was an issue with the Q8/Q9/Q10 output transistors, but a scope showed similar output signals on each (i.e. colour information).

If I select Colour Test as the profile in the Main Menu, I just get a flashing screen (i.e. black, then back to the menu).

I have tried reprogramming the CPLD to RGB/YUV etc, this makes no difference.

Does this sound like a bad CPLD?

IanSB commented 3 months ago

@axmandm

I only got a green output from my BBC Master.

Do you mean green text or just a blank green screen? Is it a digital board with fixed cable or one with the analog extender and interchangeable cables (which can also be used with the BBC)?

If I select Colour Test as the profile in the Main Menu, I just get a flashing screen (i.e. black, then back to the menu). I have tried reprogramming the CPLD to RGB/YUV etc, this makes no difference.

What CPLD was programmed when you got the flashing? Does the CPLD programming appear to proceed and finish normally as expected? (Which means the CPLD is at least partially working)

Does this sound like a bad CPLD?

Possibly, but it could be several other things too like monitor problems, corrupted software, broken wires in the DIN plug or the IDC connector getting unplugged from the 12 way header on the CPLD board.

First thing to try would be to make sure the HDMI cable was fully plugged in at both ends (or try another cable or even another monitor if you have one), then update the software to the latest release in case your existing SD card got corrupted in some way. (Reformat the SD card first, don't overwrite the existing files.) Then check the connections in the 6 way DIN connector and the 12 way IDC connector on the other end of the cable (assuming a digital board).

It might be useful if you posted screencaps of the source summary page and the system summary page in the info menu (make sure a suitable BBC or Master profile is selected). Press Up and Down simultaneously while in those pages to screencap the output with files saved to the SD card.