thermostat/src/ad7172/adc.rs

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use core::fmt;
use embedded_hal::digital::v2::OutputPin;
use embedded_hal::blocking::spi::Transfer;
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use log::{info, warn};
use super::{
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regs::{self, Register, RegisterData},
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checksum::{ChecksumMode, Checksum},
AdcError, Mode, Input, RefSource, PostFilter, DigitalFilterOrder,
};
/// AD7172-2 implementation
///
/// [Manual](https://www.analog.com/media/en/technical-documentation/data-sheets/AD7172-2.pdf)
pub struct Adc<SPI: Transfer<u8>, NSS: OutputPin> {
spi: SPI,
nss: NSS,
checksum_mode: ChecksumMode,
}
impl<SPI: Transfer<u8, Error = E>, NSS: OutputPin, E: fmt::Debug> Adc<SPI, NSS> {
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pub fn new(spi: SPI, mut nss: NSS) -> Result<Self, AdcError<SPI::Error>> {
let _ = nss.set_high();
let mut adc = Adc {
spi, nss,
checksum_mode: ChecksumMode::Off,
};
adc.reset()?;
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adc.set_checksum_mode(ChecksumMode::Crc).unwrap();
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let mut retries = 0;
let mut adc_id;
loop {
adc_id = adc.identify()?;
if adc_id & 0xFFF0 == 0x00D0 {
break;
} else {
retries += 1;
}
}
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info!("ADC id: {:04X} ({} retries)", adc_id, retries);
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let mut adc_mode = <regs::AdcMode as Register>::Data::empty();
adc_mode.set_ref_en(true);
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adc_mode.set_mode(Mode::ContinuousConversion);
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adc.write_reg(&regs::AdcMode, &mut adc_mode)?;
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Ok(adc)
}
/// `0x00DX` for AD7172-2
pub fn identify(&mut self) -> Result<u16, AdcError<SPI::Error>> {
self.read_reg(&regs::Id)
.map(|id| id.id())
}
pub fn set_checksum_mode(&mut self, mode: ChecksumMode) -> Result<(), AdcError<SPI::Error>> {
// Cannot use update_reg() here because checksum_mode is
// updated between read_reg() and write_reg().
let mut ifmode = self.read_reg(&regs::IfMode)?;
ifmode.set_crc(mode);
self.checksum_mode = mode;
self.write_reg(&regs::IfMode, &mut ifmode)?;
Ok(())
}
pub fn set_sync_enable(&mut self, enable: bool) -> Result<(), AdcError<SPI::Error>> {
self.update_reg(&regs::GpioCon, |data| {
data.set_sync_en(enable);
})
}
pub fn setup_channel(
&mut self, index: u8, in_pos: Input, in_neg: Input
) -> Result<(), AdcError<SPI::Error>> {
self.update_reg(&regs::SetupCon { index }, |data| {
data.set_bipolar(false);
data.set_refbuf_pos(true);
data.set_refbuf_neg(true);
data.set_ainbuf_pos(true);
data.set_ainbuf_neg(true);
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data.set_ref_sel(RefSource::Internal);
})?;
self.update_reg(&regs::FiltCon { index }, |data| {
data.set_enh_filt_en(true);
data.set_enh_filt(PostFilter::F16SPS);
data.set_order(DigitalFilterOrder::Sinc5Sinc1);
})?;
self.update_reg(&regs::Channel { index }, |data| {
data.set_setup(index);
data.set_enabled(true);
data.set_a_in_pos(in_pos);
data.set_a_in_neg(in_neg);
})?;
Ok(())
}
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/// Calibrates offset registers
pub fn calibrate_offset(&mut self) -> Result<(), AdcError<SPI::Error>> {
self.update_reg(&regs::AdcMode, |adc_mode| {
adc_mode.set_mode(Mode::SystemOffsetCalibration);
})?;
while ! self.read_reg(&regs::Status)?.ready() {}
self.update_reg(&regs::AdcMode, |adc_mode| {
adc_mode.set_mode(Mode::ContinuousConversion);
})?;
Ok(())
}
pub fn get_postfilter(&mut self, index: u8) -> Result<Option<PostFilter>, AdcError<SPI::Error>> {
self.read_reg(&regs::FiltCon { index })
.map(|data| {
if data.enh_filt_en() {
Some(data.enh_filt())
} else {
None
}
})
}
pub fn set_postfilter(&mut self, index: u8, filter: Option<PostFilter>) -> Result<(), AdcError<SPI::Error>> {
self.update_reg(&regs::FiltCon { index }, |data| {
match filter {
None => data.set_enh_filt_en(false),
Some(filter) => {
data.set_enh_filt_en(true);
data.set_enh_filt(filter);
}
}
})
}
/// Returns the channel the data is from
pub fn data_ready(&mut self) -> Result<Option<u8>, AdcError<SPI::Error>> {
self.read_reg(&regs::Status)
.map(|status| {
if status.ready() {
Some(status.channel())
} else {
None
}
})
}
/// Get data
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pub fn read_data(&mut self) -> Result<u32, AdcError<SPI::Error>> {
self.read_reg(&regs::Data)
.map(|data| data.data())
}
fn read_reg<R: regs::Register>(&mut self, reg: &R) -> Result<R::Data, AdcError<SPI::Error>> {
let mut reg_data = R::Data::empty();
let address = 0x40 | reg.address();
let mut checksum = Checksum::new(self.checksum_mode);
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checksum.feed(&[address]);
let checksum_out = checksum.result();
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loop {
let checksum_in = self.transfer(address, reg_data.as_mut(), checksum_out)?;
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checksum.feed(&reg_data);
let checksum_expected = checksum.result();
if checksum_expected == checksum_in {
break;
}
// Retry
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warn!("read_reg {:02X}: checksum error: {:?}!={:?}, retrying", reg.address(), checksum_expected, checksum_in);
}
Ok(reg_data)
}
fn write_reg<R: regs::Register>(&mut self, reg: &R, reg_data: &mut R::Data) -> Result<(), AdcError<SPI::Error>> {
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loop {
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let address = reg.address();
let mut checksum = Checksum::new(match self.checksum_mode {
ChecksumMode::Off => ChecksumMode::Off,
// write checksums are always crc
ChecksumMode::Xor => ChecksumMode::Crc,
ChecksumMode::Crc => ChecksumMode::Crc,
});
checksum.feed(&[address]);
checksum.feed(&reg_data);
let checksum_out = checksum.result();
let mut data = reg_data.clone();
let checksum_in = self.transfer(address, data.as_mut(), checksum_out)?;
let readback_data = self.read_reg(reg)?;
if *readback_data == **reg_data {
return Ok(());
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}
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warn!("write_reg {:02X}: readback error, {:?}!={:?}, retrying", address, &*readback_data, &**reg_data);
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}
}
fn update_reg<R, F, A>(&mut self, reg: &R, f: F) -> Result<A, AdcError<SPI::Error>>
where
R: regs::Register,
F: FnOnce(&mut R::Data) -> A,
{
let mut reg_data = self.read_reg(reg)?;
let result = f(&mut reg_data);
self.write_reg(reg, &mut reg_data)?;
Ok(result)
}
pub fn reset(&mut self) -> Result<(), SPI::Error> {
let mut buf = [0xFFu8; 8];
let _ = self.nss.set_low();
let result = self.spi.transfer(&mut buf);
let _ = self.nss.set_high();
result?;
Ok(())
}
fn transfer<'w>(&mut self, addr: u8, reg_data: &'w mut [u8], checksum: Option<u8>) -> Result<Option<u8>, SPI::Error> {
let mut addr_buf = [addr];
let _ = self.nss.set_low();
let result = match self.spi.transfer(&mut addr_buf) {
Ok(_) => self.spi.transfer(reg_data),
Err(e) => Err(e),
};
let result = match (result, checksum) {
(Ok(_),None) =>
Ok(None),
(Ok(_), Some(checksum_out)) => {
let mut checksum_buf = [checksum_out; 1];
match self.spi.transfer(&mut checksum_buf) {
Ok(_) => Ok(Some(checksum_buf[0])),
Err(e) => Err(e),
}
}
(Err(e), _) =>
Err(e),
};
let _ = self.nss.set_high();
result
}
}