add Channels::calibrate_dac_value()

This commit is contained in:
Astro 2020-05-19 00:15:39 +02:00
parent 70127491f6
commit e6e150dac3
4 changed files with 61 additions and 9 deletions

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@ -6,7 +6,6 @@ use stm32f4xx_hal::{
time::MegaHertz, time::MegaHertz,
spi, spi,
}; };
use crate::units::Volts;
/// SPI Mode 1 /// SPI Mode 1
pub const SPI_MODE: spi::Mode = spi::Mode { pub const SPI_MODE: spi::Mode = spi::Mode {
@ -45,9 +44,7 @@ impl<SPI: Transfer<u8>, S: OutputPin> Dac<SPI, S> {
Ok(()) Ok(())
} }
pub fn set(&mut self, voltage: Volts) -> Result<(), SPI::Error> { pub fn set(&mut self, value: u32) -> Result<(), SPI::Error> {
let value = ((voltage.0 * (MAX_VALUE as f64) / 5.0) as u32)
.min(MAX_VALUE);
let buf = [ let buf = [
(value >> 14) as u8, (value >> 14) as u8,
(value >> 6) as u8, (value >> 6) as u8,

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@ -2,7 +2,6 @@ use crate::{
ad5680, ad5680,
channel_state::ChannelState, channel_state::ChannelState,
pins::{ChannelPins, ChannelPinSet}, pins::{ChannelPins, ChannelPinSet},
units::Volts,
}; };
/// Marker type for the first channel /// Marker type for the first channel
@ -16,6 +15,8 @@ pub struct Channel<C: ChannelPins> {
pub state: ChannelState, pub state: ChannelState,
/// for `i_set` /// for `i_set`
pub dac: ad5680::Dac<C::DacSpi, C::DacSync>, pub dac: ad5680::Dac<C::DacSpi, C::DacSync>,
/// 1 / Volts
pub dac_factor: f64,
pub shdn: C::Shdn, pub shdn: C::Shdn,
/// stm32f4 integrated adc /// stm32f4 integrated adc
pub adc: C::Adc, pub adc: C::Adc,
@ -30,11 +31,13 @@ impl<C: ChannelPins> Channel<C> {
pub fn new(pins: ChannelPinSet<C>) -> Self { pub fn new(pins: ChannelPinSet<C>) -> Self {
let state = ChannelState::default(); let state = ChannelState::default();
let mut dac = ad5680::Dac::new(pins.dac_spi, pins.dac_sync); let mut dac = ad5680::Dac::new(pins.dac_spi, pins.dac_sync);
let _ = dac.set(Volts(0.0)); let _ = dac.set(0);
// sensible dummy preset. calibrate_i_set() must be used.
let dac_factor = ad5680::MAX_VALUE as f64 / 5.0;
Channel { Channel {
state, state,
dac, dac, dac_factor,
shdn: pins.shdn, shdn: pins.shdn,
adc: pins.adc, adc: pins.adc,
vref_pin: pins.vref_pin, vref_pin: pins.vref_pin,

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@ -1,6 +1,8 @@
use stm32f4xx_hal::hal::digital::v2::OutputPin; use stm32f4xx_hal::hal::digital::v2::OutputPin;
use smoltcp::time::Instant; use smoltcp::time::Instant;
use log::info;
use crate::{ use crate::{
ad5680,
ad7172, ad7172,
channel::{Channel, Channel0, Channel1}, channel::{Channel, Channel0, Channel1},
channel_state::ChannelState, channel_state::ChannelState,
@ -83,14 +85,21 @@ impl Channels {
/// i_set DAC /// i_set DAC
pub fn set_dac(&mut self, channel: usize, voltage: Volts) { pub fn set_dac(&mut self, channel: usize, voltage: Volts) {
let dac_factor = match channel.into() {
0 => self.channel0.dac_factor,
1 => self.channel1.dac_factor,
_ => unreachable!(),
};
let value = (voltage.0 * dac_factor) as u32;
info!("set_dac {} {}", voltage, value);
match channel { match channel {
0 => { 0 => {
self.channel0.dac.set(voltage).unwrap(); self.channel0.dac.set(value).unwrap();
self.channel0.state.dac_value = voltage; self.channel0.state.dac_value = voltage;
self.channel0.shdn.set_high().unwrap(); self.channel0.shdn.set_high().unwrap();
} }
1 => { 1 => {
self.channel1.dac.set(voltage).unwrap(); self.channel1.dac.set(value).unwrap();
self.channel1.state.dac_value = voltage; self.channel1.state.dac_value = voltage;
self.channel1.shdn.set_high().unwrap(); self.channel1.shdn.set_high().unwrap();
} }
@ -142,6 +151,7 @@ impl Channels {
} }
} }
/// should be 1.5V
pub fn read_vref(&mut self, channel: usize) -> Volts { pub fn read_vref(&mut self, channel: usize) -> Volts {
match channel { match channel {
0 => { 0 => {
@ -185,4 +195,44 @@ impl Channels {
_ => unreachable!(), _ => unreachable!(),
} }
} }
/// for i_set
pub fn calibrate_dac_value(&mut self, channel: usize) {
let vref = self.read_vref(channel);
let mut best_value = 0;
let mut best_error = Volts(100.0);
for value in 1..=ad5680::MAX_VALUE {
match channel {
0 => {
self.channel0.dac.set(value).unwrap();
self.channel0.shdn.set_high().unwrap();
}
1 => {
self.channel1.dac.set(value).unwrap();
self.channel1.shdn.set_high().unwrap();
}
_ => unreachable!(),
}
let dac_feedback = self.read_dac_feedback(channel);
let error = vref - dac_feedback;
if error < Volts(0.0) {
info!("calibration done at {} > {}", dac_feedback, vref);
break;
} else if error < best_error {
best_value = value;
best_error = error;
}
}
self.set_dac(channel, Volts(0.0));
info!("best dac value for {}: {}, itec={}", vref, best_value, self.read_itec(channel));
let dac_factor = best_value as f64 / vref.0;
match channel {
0 => self.channel0.dac_factor = dac_factor,
1 => self.channel1.dac_factor = dac_factor,
_ => unreachable!(),
}
}
} }

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@ -96,6 +96,8 @@ fn main() -> ! {
dp.ADC1, dp.ADC2, dp.ADC3, dp.ADC1, dp.ADC2, dp.ADC3,
); );
let mut channels = Channels::new(pins); let mut channels = Channels::new(pins);
channels.calibrate_dac_value(0);
timer::setup(cp.SYST, clocks); timer::setup(cp.SYST, clocks);
#[cfg(not(feature = "generate-hwaddr"))] #[cfg(not(feature = "generate-hwaddr"))]