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Forum Index : Microcontroller and PC projects : Picomite VGA: VGA to HDMI-converter doesn't work

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Mixtel90

Guru

Joined: 05/10/2019
Location: United Kingdom
Posts: 8899
Posted: 01:49pm 15 Jun 2026
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As far as the VGA output from the Pico goes there is virtually nothing to go wrong. Even the RGB signals are from ordinary digital outputs mixed by the resistors. There is no outgoing power, only a GND so everything is at VGA signal levels. Providing you are running the VGA firmware and haven't messed about with the VGA PINS option you will get a VGA signal of some sort on the standard pins. Resistor values have been pre-calculated for the standard 75R inputs of VGA monitors.

Converting from an HDMI output to a VGA input is usually cheap and cheerful. I've had   very cheap converters that will do that from a Raspberry Pi.

Converting from a VGA output to HDMI input is far more complex and can be much more demanding.It more or less demands specialist chips. Converters that would do it used to be relatively expensive. The RP2350 can generate DVI (a "cut down" version of HDMI) using the HSTX module to get the necessary very close tolerance timing correct.

If you have VGA working and that converts to HDMI that works with one display but not with another then the fault is very likely to be with the data acceptance tolerance of the non-working display. It may work at some resolutions but not at others. Such is HDMI. :(
Mick

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v.lenzer
Senior Member

Joined: 04/05/2024
Location: Germany
Posts: 117
Posted: 02:58pm 15 Jun 2026
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  Quote  If you have VGA working and that converts to HDMI that works with one display but not with another then the fault is very likely to be with the data acceptance tolerance of the non-working display. It may work at some resolutions but not at others. Such is HDMI. :(


Yes, that’s the conclusion I reached as well. The signals are correct and the connections are in place, but the converter chip simply doesn't like the signals. No matter—I’ve found a solution using my PC monitor now.
Edited 2026-06-16 00:58 by v.lenzer
Best wishes! Joachim
 
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