Minimal example of DCD support in `imxrt-rs`

build.rs

use std::io::Result;

use imxrt_ral as ral;

macro_rules! reg_addr {
    ($block:expr, $reg:ident) => {
        unsafe { ::core::ptr::addr_of!((*($block)).$reg) as u32 }
    }
}

fn build_dcd() -> Result<()> {
    use imxrt_dcd::*;
    let command = [
        // clock gating for GPIO2
        Command::Write(Write {
            width: Width::B4,
            op: WriteOp::Set,
            address: reg_addr!(ral::ccm::CCM, CCGR0),
            value: (0b11 << ral::ccm::CCGR0::CG15::offset),
        })
        // clock gating for IOMUXC
        Command::Write(Write {
            width: Width::B4,
            op: WriteOp::Set,
            address: reg_addr!(ral::ccm::CCM, CCGR4),
            value: (0b11 << ral::ccm::CCGR4::CG1::offset),
        })
        // LED pin mux to GPIO
        Command::Write(Write {
            width: Width::B4,
            op: WriteOp::Write,
            address: reg_addr!(ral::iomuxc::IOMUXC, SW_MUX_CTL_PAD_GPIO_B0_03),
            value: 5,
        })
        // LED pin config --- max strength output
        Command::Write(Write {
            width: Width::B4,
            op: WriteOp::Write,
            address: reg_addr!(ral::iomuxc::IOMUXC, SW_PAD_CTL_PAD_GPIO_B0_03),
            value: (0b111 << ral::iomuxc::SW_PAD_CTL_PAD_GPIO_B0_03::DSE::offset),
        })
        Command::Check(Check {
            width: Width::B4,
            cond: CheckCond::AllSet,
            address: reg_addr!(ral::iomuxc::IOMUXC, SW_PAD_CTL_PAD_GPIO_B0_03),
            mask: (7 << 3),
            count: None,
        })
    ];

    let path = std::path::PathBuf::from(std::env::var_os("OUT_DIR").unwrap()).join("dcd.bin");
    let f = std::fs::File::create(&path)?;
    serialize(f, &command)?;
    Ok(())
}

main.rs

#![no_std]
#![no_main]

use imxrt_ral as ral;
use teensy4_fcb as _;
use teensy4_panic as _;

mod led;  // omitted (this really is just teensy4_panic with everything public)

/***************************************************/
static_include_bytes!(
    #[no_mangle]
    #[link_section = ".dcd"]
    DCD = concat!(env!("OUT_DIR"), "/dcd.bin")
);
/***************************************************/


#[imxrt_rt::entry]
fn main() -> ! {
    const D1: led::DelayTicks = led::DelayTicks::new(1);
    const D3: led::DelayTicks = led::DelayTicks::new(3);
    const D6: led::DelayTicks = led::DelayTicks::new(6);
    const D9: led::DelayTicks = led::DelayTicks::new(9);

    let iomuxc = unsafe { ral::iomuxc::IOMUXC::instance() };
    let mux_reg = ral::read_reg!(ral::iomuxc, iomuxc, SW_MUX_CTL_PAD_GPIO_B0_03);
    let pad_reg = ral::read_reg!(ral::iomuxc, iomuxc, SW_PAD_CTL_PAD_GPIO_B0_03);

    let mut led = unsafe { led::Led::new() };
    for i in 0..8 {
        led.set();
        led::delay(if (mux_reg & (1 << i)) != 0 { D3 } else { D1 });
        led.clear();
        led::delay(if (mux_reg & (1 << i)) != 0 { D1 } else { D3 });
    }
    led::delay(D9);
    for i in 0..16 {
        led.set();
        led::delay(if (pad_reg & (1 << i)) != 0 { D3 } else { D1 });
        led.clear();
        led::delay(if (pad_reg & (1 << i)) != 0 { D1 } else { D3 });
    }

    loop{}
}