pmu_sleep2.rs

#![no_std]
#![no_main]

/*
* Basic blinking LEDs example using pmu sleep
* for "sleep" in a loop. Blinks each led once and goes to the next one.
*/

extern crate panic_halt;

use riscv_rt::entry;
use hifive1::hal::prelude::*;
use hifive1::hal::e310x::Peripherals;
use hifive1::sprintln;

const PMU_KEY_VAL: u32 = 0x51F15E;

const SLEEP_PROGRAM: [u32; 8] = [
    0x2F0, // assert corerst
    0x3F0, // assert hfclkrst
    0x3D0, // deassert pmu_out_1
    0x3C0, // deassert pmu_out_0
    0x3C0, // repeats
    0x3C0,
    0x3C0,
    0x3C0,
];

const WAKE_PROGRAM: [u32; 8] = [
    0x3F0, // assert all resets and enable all power supplies
    0x2F8, // idle 2^8 cycles, then deassert hfclkrst
    0x030, // deassert corerst and padrst
    0x030, // repeats
    0x030, 
    0x030,
    0x030,
    0x030,
];

#[entry]
fn main() -> ! {
    let p = Peripherals::take().unwrap();
    let gpio = p.GPIO0.split();

    // Configure clocks
    let clocks = hifive1::clock::configure(p.PRCI, p.AONCLK, 320.mhz().into());

    // Configure UART for stdout
    hifive1::stdout::configure(p.UART0, gpio.pin17, gpio.pin16, 115_200.bps(), clocks);

    // set correct sleep and wake programs
    unsafe {
        for i in 0..7 {
            p.PMU.pmukey.write(|w| w.bits(PMU_KEY_VAL));
            p.PMU.pmusleeppm[i].write(|w| w.bits(SLEEP_PROGRAM[i]));
            // sprintln!("Set sleep p[{}] = 0x{:X}", i, SLEEP_PROGRAM[i]);

            p.PMU.pmukey.write(|w| w.bits(PMU_KEY_VAL));
            p.PMU.pmuwakepm[i].write(|w| w.bits(WAKE_PROGRAM[i]));
            // sprintln!("Set wake p[{}] = 0x{:X}", i, WAKE_PROGRAM[i]);
        }
    }

    // let mut i = 0;
    // for sr in &p.PMU.pmusleeppm {
    //     sprintln!("Sleep instr{} = 0x{:X}", i, sr.read().bits());
    //     i = i + 1;
    // }

    // i = 0;
    // for wr in &p.PMU.pmuwakepm {
    //     sprintln!("Wake instr{} = 0x{:X}", i, wr.read().bits());
    //     i = i + 1;
    // }

    sprintln!("Going to sleep");
    
    unsafe {
        // set interrupt source to RTC enabled, each pmu register needs key set before write
        p.PMU.pmukey.write(|w| w.bits(PMU_KEY_VAL));
        p.PMU.pmuie.write(|w| w.rtc().set_bit());
        // set RTC clock scale to once per second for easy calculation
        p.RTC.rtccfg.write(|w| w.scale().bits(15));
        // get current RTC clock value scaled
        let rtc_now = p.RTC.rtcs.read().bits();
        // set RTC clock comparator
        p.RTC.rtccmp.write(|w| w.bits(rtc_now + 15)); // 15 second delay on sleep
        // go to sleep for 15s, need to set pmukey here as well
        p.PMU.pmukey.write(|w| w.bits(PMU_KEY_VAL));
        p.PMU.pmusleep.write(|w| w.bits(0xFFFF));
    }

    sprintln!("EOL");

    loop {}
}