can_speedtest.rs

//! # Point-to-point speedtest
//! This program sllows you to strobe the CAN network with a single packet whose
//! starting time is known. Simply run the program, setup your oscilloscope to
//! probe the GPIO output and measure the time taken between rise and fall.
//!
//! At some point, the timer will trigger to send your CAN output, which makes
//! the breakpoint trigger, allowing you to setup single-edge triggering.
//!
//! *REMEMBER: Using debug mode builds will yield _very_ pessimistic results.*

#![feature(panic_info_message)]
#![no_main]
#![no_std]
extern crate panic_halt;

// CAN driver
use lpc43xx_hal::{
    can::{CanBus, MsgIface, MsgObj},
    pac,
    timer::{InterruptType, Timer},
};
use pac::c_can1::cntl::{DAR_A, EIE_A, IE_A, SIE_A};

static TIMER_PERIOD: u32 = 8192;

use rtfm::app;

use heapless::consts::U32;

#[app(device = lpc43xx_pac)]
const APP: () = {
    static mut GPIO: pac::GPIO_PORT = ();
    static mut TIMER: Timer<pac::TIMER0> = ();
    static mut CAN_0: CanBus<pac::C_CAN0, U32> = ();
    static mut CAN_1: CanBus<pac::C_CAN1, U32> = ();
    static mut RX_OBJ: MsgObj = ();
    static mut TX_OBJ: MsgObj = ();
    static mut TX_STATE: u8 = ();

    #[init]
    fn init() -> init::LateResources {
        let tx_state: u8 = 0;

        // ========= TIMER INITIALIZATION ==========
        let timer = Timer::<pac::TIMER0>::new(device.TIMER0);
        timer.start_timer(false);
        timer.set_match(0, TIMER_PERIOD);
        timer.set_prescaler(1024, Some(0));
        timer.mr0(true, true, false);
        timer.start_timer(true);

        // ========= GPIO SETUP  =========
        device.SCU.sfsp7_7.write(|w| w.mode().function_0_default());
        device.GPIO_PORT.dir[3].write(|w| w.dirp15().set_bit());
        device.GPIO_PORT.clr[3].write(|w| w.clrp015().set_bit());

        // ========= CAN 0 INITIALIZATION ==========
        let mut can_0 = CanBus::<pac::C_CAN0, U32>::new(device.C_CAN0);
        device
            .SCU
            .sfspe_3
            .write(|w| w.mode().function_1().epun().bit(true)); // CAN0_TD
        device
            .SCU
            .sfspe_2
            .write(|w| w.mode().function_1().epun().bit(true).ezi().bit(true)); // CAN0_RD

        can_0.initialize(
            12_000_000,
            500000,