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VGA driver using PIO and DMA on the RP2040

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Re: VGA driver using PIO and DMA on the RP2040

#4

Post by cdcarter »

_Microft wrote: post #2

OT but a question I'm curious about: what features would people who have a lot of experience with the RP2040 like to see on a successor?

Another pair of PIO blocks (and two more DMA channels) is my desire. I think a lot of people would love to see a (slightly more expensive) variant with more uncommitted GPIOs.

My pet projects with the Pico and clones involve interfacing with an 8-bit processor, and the RP2040 just doesn’t expose enough pins for the full data, address, and control busses AND actually doing something interesting with the outside world.

Another dedicated USB PHY peripheral would also be great, a lot of people lose a PIO block to adding a second USB port. Obviously this also shows the power of PIO, but it’s nice to be able to reserve those blocks for more obscure physical things.

I bet a lot of people would like more analog pins, the Teensy provides a lot more, for example.

Re: VGA driver using PIO and DMA on the RP2040

#8

Post by vinkelhake »

Here's another [1] project that does VGA output from an RP2040 (the project also includes some game). There's also some support for VGA in the pico_extras [2] repo.

[1] https://kilograham.github.io/rp2040-doom/ [2] https://github.com/raspberrypi/pico-extras/tree/master/src/c...

Re: VGA driver using PIO and DMA on the RP2040

#9

Post by raphlinus »

andrewstuart wrote: post #7

Related: Adafruit Feather RP2040 with HDMI Output Port https://youtu.be/Nsvf5gnYErs https://www.adafruit.com/product/5710 Generating PAL https://hackaday.com/2023/01/24/generating-pal-video-with-a-...

I have the Adafruit DVI board and have been hacking on it some. It's more fun than should be allowed.

There's a project to get this running using Rust[1]. Currently it outputs the blue channel with sync, but has trouble with the other two channels. I don't have a hardware lab with scope, logic analyzer, etc., so it's not easy for me to debug.

In the meantime, I've been doing some experiments in the C codebase as well[2], mostly in the direction of proportionally spaced bitmap text, using the fonts in the X11 distribution.

[1]: https://github.com/DusterTheFirst/pico-dvi-rs

[2]: https://github.com/Wren6991/PicoDVI/pull/48

Re: VGA driver using PIO and DMA on the RP2040

#10

Post by vardump »

boricj wrote: post #3

This reminds me of the Uzebox [1], a video game console based on an ATMega644, but the RP2040 in this looks far more powerful at a glance. How far could this realistically be pushed? [1] https://uzebox.org/

At least this far. https://www.youtube.com/watch?v=eDVazQVycP4

RP2040 running Doom, includes VGA, Adlib emulation, PCM sound effects, 4 player "LAN". Pretty much the same experience as Doom on a DOS PC.

264 kB of total RAM is the main restriction.

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