pico-extras VS rpi

In the Pico Extras repository, find the external/pico_extras_import.cmake file

[2] https://github.com/raspberrypi/pico-extras/tree/master/src/c...

pico-extras

There is https://github.com/raspberrypi/pico-extras/tree/master/src/rp2_common/pico_sd_card which is SDIO based, and works for reading/writing sectors, but very bare bones prototype atm.

I've just been getting to grips with the PIO, they are a lot of fun to program. Whilst the instruction set is very limited with only enough memory for 32 of them you can do some pretty sophisticated things. A key part of the flexibility is the ability to execute incoming data as instructions. You can stream in a mixture of data and instructions via the DMA, the PIO separates the two and uses the instructions to modify execution so a simple loop becomes a lot more flexible. You can easily sync several of them up to. The scanvideo library: https://github.com/raspberrypi/pico-extras/blob/master/src/c... which is for producing video signals (like VGA) on the fly with scanlines supplied by the CPU is a good example of what's possible. You can have multiple scanline PIO running at once, each decoding a compressed RLE format including transparency and it composes them all together on the fly.

If you've ever played one of the Zachtronics games (in particular Shenzhen IO) it feels like the programming in one of those games. Tight constraints but major possibilities when you think about it for a while.

You can see the startup assembly I use here: https://github.com/blippy/rpi/blob/master/stm32f411re/cmsis/01-blink/startup_stm32f411retx.s

If you're happy about using the SDK, but don't want VS, then a simple template is here: https://github.com/blippy/rpi/tree/master/pico/0TEMPLATE

I have managed to interface to an SD card as a block device, no file system. I was able to play audio that I dumped to the card. The project is here: https://github.com/blippy/rpi/tree/master/pico/sdcard It is not feature-complete (it doesn't write to cards, and only supports version 2 cards), but hey, it is at least a proof-if-concept that it is doable.

Write-up: https://github.com/blippy/rpi/blob/master/pico/baby.md

I have a working uart here: https://github.com/blippy/rpi/blob/master/stm8s103f3p6/bare8/05-uart/main.c 115200 baud