picodvi VS Arduino_STM32

The RP2040 is a great MCU for playing with graphics as it can bit bang VGA and DVI/HDMI. There's some info on the DVI here: https://github.com/Wren6991/PicoDVI

I wrote a couple of articles on how to do bit banged VGA on the RP2040 from scratch: https://gregchadwick.co.uk/blog/playing-with-the-pico-pt5/ and https://gregchadwick.co.uk/blog/playing-with-the-pico-pt6/ plus an intro to PIO https://gregchadwick.co.uk/blog/playing-with-the-pico-pt4/

A few years back someone was bit banging DVI and 720p 30fps video straight off the RP2040 GPIO pins with just inline resistors between not and the HDMI cable.

https://github.com/Wren6991/PicoDVI

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

There is even bit-banged DVI library for pico.

Apparently, there is a digital video output project for the RP2040 already out there [0]! As for why digital video is more rare, it is because the common digital video formats are higher bandwidth and require higher signal integrity.

[0] https://github.com/Wren6991/PicoDVI

I've seen people implement DVI with PIO, and I'm sure basic missile commands wouldn't be as bandwidth-intensive as that.

For example this guy (https://github.com/Wren6991/PicoDVI) essentially 'bit bangs' CML. Sure its not a completely compliant implementation, but it's pretty close... In his case using a push pull with 3.3V/0V. I don't know how he's getting a 0.8V swing.

2 https://github.com/rogerclarkmelbourne/Arduino_STM32/tree/master/STM32F1/libraries/Adafruit_SSD1306

I had to get these files: https://github.com/rogerclarkmelbourne/Arduino_STM32/tree/master/drivers/win and run the install_drivers.bat The maple bootloader goes by too quick to inspect its device manager entry normally. So, I'd turned on "show hidden devices" to inspect it. Prior to running that batch file to install the drivers and resetting, the DRiver Provider was Unknown, Driver date unavalaiable and so on. Afterwards it shows Driver provider libusb-win32, and other details filled in. So, that is necessary. To use the maple loader that you'd burned on Windows.

Straight out the box the rogerclarkmelbourne Arduino_STM32 core is fastest at 166,666 analog reads per second. https://github.com/rogerclarkmelbourne/Arduino_STM32

(libmaple) Roger's

My go-to Arduino nowadays is a STM32F1 (using roger's libmaple): super cheap and powerfull.