Current stepping via transistor DAC

This commit is contained in:
JP Stringham
2026-01-27 10:42:04 -05:00
parent 02a4856b98
commit 13789932cb

View File

@@ -35,9 +35,6 @@ pub static BOOT2: [u8; 256] = rp2040_boot2::BOOT_LOADER_GENERIC_03H;
/// if your board has a different frequency
const XTAL_FREQ_HZ: u32 = 12_000_000u32;
// below this we won't be able to turn on the transistor (0.6v)
const MIN_DUTY: u16 = 6000;
#[rp2040_hal::entry]
fn main() -> ! {
// Grab our singleton objects
@@ -79,33 +76,19 @@ fn main() -> ! {
.clock_divider(47999, 0)
.start_paused();
let mut pwm_slices = hal::pwm::Slices::new(pac.PWM, &mut pac.RESETS);
let pwm = &mut pwm_slices.pwm2;
// info!("PWM Top: {}", pwm.get_top());
pwm.set_ph_correct();
pwm.enable();
let pwm_channel = &mut pwm.channel_a;
pwm_channel.output_to(pins.gpio20);
pwm_channel.set_duty_cycle(MIN_DUTY);
// calibrate
delay.delay_ms(2000);
// let mut led_pin = pins.gpio25.into_push_pull_output();
let mut duty = MIN_DUTY;
let mut power = 0;
let mut tick = 19u8;
let mut tick = 0u8;
let mut peak_v = 0u32;
loop {
pwm_channel.set_duty_cycle(duty);
let mut current_pins = [
pins.gpio16.into_push_pull_output().into_dyn_pin(),
pins.gpio17.into_push_pull_output().into_dyn_pin(),
pins.gpio18.into_push_pull_output().into_dyn_pin(),
];
loop {
delay.delay_ms(500);
adc_fifo.clear();
adc_fifo.resume();
@@ -116,42 +99,17 @@ fn main() -> ! {
adc_fifo.pause();
let mut samps = [0u16; 8];
for (i, cp) in current_pins.iter_mut().enumerate() {
let mask = 0b1 << i;
for i in 0..8 {
samps[i] = adc_fifo.read();
if mask & tick > 0 {
cp.set_high();
} else {
cp.set_low();
}
}
let avg = avg_fifo(&samps, false);
let voltage = (avg * 3300) / 4095;
let duty_as_pct = (duty - MIN_DUTY) as u32 * 100;
let duty_as_pct = duty_as_pct / (0xFFFF - MIN_DUTY) as u32;
let new_power = (voltage * (1 + voltage / 100)) * duty_as_pct;
tick = (tick + 1) % 20;
if tick == 0 {
info!(
"{} duty, {}mV, {} power, {} peak",
duty_as_pct, voltage, new_power, peak_v
);
}
if duty_as_pct == 0 || voltage > peak_v {
peak_v = voltage;
}
duty = duty.wrapping_add(1000);
duty = MIN_DUTY.max(duty);
// if voltage > (90 * peak_v) / 100 || new_power >= power {
// duty = duty.saturating_add(33);
// } else {
// duty = MIN_DUTY.max(duty - 32);
// }
power = new_power;
tick = (tick + 1) % 8;
}
}