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#![no_std]
#![no_main]
#![feature(abi_avr_interrupt)]
#![feature(asm_experimental_arch)]
#![feature(asm_const)]
use avr_device::atmega8::{Peripherals, PORTB, PORTC, PORTD, TC1, TC2};
pub fn ports_init(pb: &PORTB, pc: &PORTC, pd: &PORTD) {
fn pin_input(_bit: usize) -> u8 {
0
}
fn pin_output(bit: usize) -> u8 {
1 << bit
}
fn pin_low(_bit: usize) -> u8 {
0
}
fn pin_floating(_bit: usize) -> u8 {
0
}
// PORTB
pb.portb.write(|w| {
unsafe {
w.bits(
pin_low(0) | // n/c
pin_low(1) | // mot
pin_low(2) | // n/c
pin_low(3) | // ISP MOSI
pin_low(4) | // ISP MISO
pin_low(5), // ISP SCK
)
}
});
pb.ddrb.write(|w| {
unsafe {
w.bits(
pin_output(0) | // n/c
pin_output(1) | // mot
pin_output(2) | // n/c
pin_output(3) | // ISP MOSI
pin_output(4) | // ISP MISO
pin_output(5), // ISP SCK
)
}
});
// PORTC
pc.portc.write(|w| {
unsafe {
w.bits(
pin_low(0) | // 50hz
pin_low(1) | // n/c
pin_low(2) | // n/c
pin_low(3) | // n/c
pin_low(4) | // n/c
pin_low(5) | // n/c
pin_low(6) | // n/c
pin_low(7), // n/c
)
}
});
pc.ddrc.write(|w| {
unsafe {
w.bits(
pin_output(0) | // 50hz
pin_output(1) | // n/c
pin_output(2) | // n/c
pin_output(3) | // n/c
pin_output(4) | // n/c
pin_output(5) | // n/c
pin_output(6) | // n/c
pin_output(7), // n/c
)
}
});
// PORTD
pd.portd.write(|w| {
unsafe {
w.bits(
pin_low(0) | // n/c
pin_low(1) | // n/c
pin_floating(2) | // trig
pin_low(3) | // n/c
pin_low(4) | // n/c
pin_low(5) | // n/c
pin_low(6) | // n/c
pin_low(7), // n/c
)
}
});
pd.ddrd.write(|w| {
unsafe {
w.bits(
pin_output(0) | // n/c
pin_output(1) | // n/c
pin_input(2) | // trig
pin_output(3) | // n/c
pin_output(4) | // n/c
pin_output(5) | // n/c
pin_output(6) | // n/c
pin_output(7), // n/c
)
}
});
}
const TIMER1_DUTYMAX: u16 = 0xFF;
fn timer1_init(tc1: &TC1) {
tc1.icr1.write(|w| w.bits(TIMER1_DUTYMAX));
tc1.ocr1a.write(|w| w.bits(0x00));
tc1.tccr1a.write(|w| {
w.com1a().match_clear()
.com1b().disconnected()
.wgm1().bits(2)
});
tc1.tccr1b.write(|w| {
w.cs1().prescale_256()
.wgm1().bits(2)
});
}
fn timer1_duty(tc1: &TC1, duty: u16) {
tc1.ocr1a.write(|w| w.bits(duty));
}
const TIMER2_MAX: u8 = 78;
fn timer2_init(tc2: &TC2) {
// Timer2 init; ctc, 100 Hz.
tc2.ocr2.write(|w| w.bits(TIMER2_MAX));
tc2.tccr2.write(|w| {
w.cs2().prescale_1024()
.wgm20().clear_bit()
.wgm21().set_bit()
});
}
fn timer2_event(tc2: &TC2) -> bool {
let ocf = tc2.tifr.read().ocf2().bit();
if ocf {
tc2.tifr.write(|w| w.ocf2().set_bit());
}
ocf
}
fn timer2_value(tc2: &TC2) -> u8 {
tc2.tcnt2.read().bits().min(TIMER2_MAX)
}
#[avr_device::entry]
fn main() -> ! {
let dp = Peripherals::take().unwrap();
ports_init(&dp.PORTB, &dp.PORTC, &dp.PORTD);
timer1_init(&dp.TC1);
timer2_init(&dp.TC2);
let mut hz50 = false;
let mut in_trig = false;
loop {
let trig = dp.PORTD.pind.read().pd2().bit();
if trig && !in_trig {
let val = TIMER2_MAX - timer2_value(&dp.TC2);
let duty = val as u16 * (TIMER1_DUTYMAX + 1) / (TIMER2_MAX as u16 + 1);
timer1_duty(&dp.TC1, duty);
}
in_trig = trig;
hz50 ^= timer2_event(&dp.TC2);
dp.PORTC.portc.modify(|_, w| w.pc0().bit(hz50));
}
}
#[panic_handler]
fn panic(_: &core::panic::PanicInfo) -> ! {
loop {}
}
// vim: ts=4 sw=4 expandtab
|
