pico-blink-rs

Running Rust code on the Raspberry Pi Pico

Booting

The RP2040 has external QSPI flash. There is an internal mask-ROM bootloader which can read the first 256 bytes of external flash and copy it to the top of SRAM (0x2004_1f00). This 256 byte block is the 'second stage bootloader'. Its job is to reconfigure the XIP_SSI interface to the right values for the attached QSPI flash chip (the mask ROM has some very conservative defaults which should work with all chips), and configure the XIP so that the QSPI flash appears at address 0x1000_0000 upwards.

The second stage bootloader then loads the user application once the XIP_SSI configuration is complete. It does this by reading a vector table at 0x1000_0100, which is 256 bytes into the QSPI flash contents (or immediately after the 256 byte second stage bootloader), and jumping to the reset vector.

We should also write a BSP for the pico, and a HAL for the RP2040. Basically, don't do any of what I did here. But hey, it blinks!

Licence

This work is licenced under CC0. Binaries may include material Copyright Raspberry Pi Trading - see other crates for details.

Comments

no field `gpio25`

Issuing cargo build

results in the output:

  Compiling pico-blink-rs v0.2.0 (/home/pi/pico-blink-rs)
error[E0609]: no field `gpio25` on type `PADS_BANK0`
   --> src/main.rs:126:18
    |
126 |     p.PADS_BANK0.gpio25.write(|w| {
    |                  ^^^^^^ unknown field

error[E0609]: no field `gpio25_ctrl` on type `IO_BANK0`
   --> src/main.rs:133:16
    |
133 |     p.IO_BANK0.gpio25_ctrl.write(|w| {
    |                ^^^^^^^^^^^ unknown field

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0609`.
error: could not compile `pico-blink-rs`

To learn more, run the command again with --verbose.

opened by blippy 2

RAM size is 264k

Maybe there is some context I am missing here and you have other plans for the 2x 4kiB banks, but the total memory is 264 kiB. Raising this because I saw someone link to the memory.x here :)

opened by Wren6991 1
Fix gpio to use array

https://github.com/rp-rs/rp2040-pac/pull/12 https://github.com/rp-rs/rp2040-pac/commit/56198b7d7f795c1bf3b7c5040f3724bf6683186f

Changes made to this dependency means PADS_BANK0 and IO_BANK0 reference gpio as arrays.

opened by sirris-bat 0