main.rs

#![no_std]
#![no_main]

extern crate panic_halt;

use picorv32_rt::entry;

const TEST: *mut u32 = 0xcafebab0 as *mut u32;

#[entry]
fn main() -> ! {
    unsafe {
        TEST.write_volatile(!0);
    }
    loop {}
}

mapping.py

self.picorv32 = PicoRV32([
    Mapping(
        addr=0xcafebab0,
        signal=self.led,
        write=True,
        read=False,
    )
    # Mapping(
    #     addr=0xf000_0000,
    #     signal=self.dds_ctrl,
    #     read=True,
    #     write=True,
    # ),
    # Mapping(
    #     addr=0xf000_0004, # offset by 1 word
    #     signal=self.dds.phase_step,
    #     read=True,
    #     write=True,
    # ),
])