Pins::setup, replace adc_input with ad7172

src/ad7172/adc.rs

@@ -0,0 +1,212 @@
+use core::fmt;
+use embedded_hal::digital::v2::OutputPin;
+use embedded_hal::blocking::spi::Transfer;
+use log::{info, warn};
+use super::checksum::{ChecksumMode, Checksum};
+use super::AdcError;
+use super::{
+    regs, regs::RegisterData,
+    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> {
+    pub fn new(spi: SPI, mut nss: NSS) -> Result<Self, SPI::Error> {
+        let _ = nss.set_high();
+        let mut adc = Adc {
+            spi, nss,
+            checksum_mode: ChecksumMode::Off,
+        };
+        adc.reset()?;
+
+        match adc.identify() {
+            Err(e) =>
+                warn!("Cannot identify ADC: {:?}", e),
+            Ok(id) if id & 0xFFF0 == 0x00D0 =>
+                info!("ADC id: {:04X}", id),
+            Ok(id) =>
+                info!("ADC id: {:04X} (corrupt)", id),
+        }
+
+        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);
+            data.set_ref_sel(RefSource::External);
+        })?;
+        self.update_reg(&regs::FiltCon { index }, |data| {
+            data.set_enh_filt_en(true);
+            data.set_enh_filt(PostFilter::F16SPS);
+            data.set_order(DigitalFilterOrder::Sinc5Sinc1);
+        })?;
+        // let mut offset = <regs::Offset as regs::Register>::Data::empty();
+        // offset.set_offset(0);
+        // self.write_reg(&regs::Offset { index }, &mut offset);
+        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(())
+    }
+
+    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
+    pub fn read_data(&mut self) -> Result<i32, 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);
+        checksum.feed(address);
+        let checksum_out = checksum.result();
+        let checksum_in = self.transfer(address, reg_data.as_mut(), checksum_out)?;
+        for &mut b in reg_data.as_mut() {
+            checksum.feed(b);
+        }
+        let checksum_expected = checksum.result();
+        if checksum_expected != checksum_in {
+            return Err(AdcError::ChecksumMismatch(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>> {
+        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);
+        for &mut b in reg_data.as_mut() {
+            checksum.feed(b);
+        }
+        let checksum_out = checksum.result();
+        self.transfer(address, reg_data.as_mut(), checksum_out)?;
+        Ok(())
+    }
+
+    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
+    }
+}

src/ad7172/checksum.rs

@@ -0,0 +1,54 @@
+#[derive(Clone, Copy, PartialEq)]
+#[repr(u8)]
+pub enum ChecksumMode {
+    Off = 0b00,
+    /// Seems much less reliable than `Crc`
+    Xor = 0b01,
+    Crc = 0b10,
+}
+
+impl From<u8> for ChecksumMode {
+    fn from(x: u8) -> Self {
+        match x {
+            0 => ChecksumMode::Off,
+            1 => ChecksumMode::Xor,
+            _ => ChecksumMode::Crc,
+        }
+    }
+}
+
+pub struct Checksum {
+    mode: ChecksumMode,
+    state: u8,
+}
+
+impl Checksum {
+    pub fn new(mode: ChecksumMode) -> Self {
+        Checksum { mode, state: 0 }
+    }
+
+    pub fn feed(&mut self, input: u8) {
+        match self.mode {
+            ChecksumMode::Off => {},
+            ChecksumMode::Xor => self.state ^= input,
+            ChecksumMode::Crc => {
+                for i in 0..8 {
+                    let input_mask = 0x80 >> i;
+                    self.state = (self.state << 1) ^
+                        if ((self.state & 0x80) != 0) != ((input & input_mask) != 0) {
+                            0x07 /* x8 + x2 + x + 1 */
+                        } else {
+                            0
+                        };
+                }
+            }
+        }
+    }
+
+    pub fn result(&self) -> Option<u8> {
+        match self.mode {
+            ChecksumMode::Off => None,
+            _ => Some(self.state)
+        }
+    }
+}

src/ad7172/mod.rs

@@ -0,0 +1,210 @@
+use core::fmt;
+use stm32f4xx_hal::{
+    time::{MegaHertz, U32Ext},
+    spi,
+};
+
+pub mod regs;
+mod checksum;
+pub use checksum::ChecksumMode;
+mod adc;
+pub use adc::*;
+
+/// SPI Mode 3
+pub const SPI_MODE: spi::Mode = spi::Mode {
+    polarity: spi::Polarity::IdleHigh,
+    phase: spi::Phase::CaptureOnSecondTransition,
+};
+/// 2 MHz
+pub const SPI_CLOCK: MegaHertz = MegaHertz(2);
+
+#[derive(Clone, Debug, PartialEq)]
+pub enum AdcError<SPI> {
+    SPI(SPI),
+    ChecksumMismatch(Option<u8>, Option<u8>),
+}
+
+impl<SPI> From<SPI> for AdcError<SPI> {
+    fn from(e: SPI) -> Self {
+        AdcError::SPI(e)
+    }
+}
+
+#[derive(Clone, Copy, Debug)]
+#[repr(u8)]
+pub enum Input {
+    Ain0 = 0,
+    Ain1 = 1,
+    Ain2 = 2,
+    Ain3 = 3,
+    Ain4 = 4,
+    TemperaturePos = 17,
+    TemperatureNeg = 18,
+    AnalogSupplyPos = 19,
+    AnalogSupplyNeg = 20,
+    RefPos = 21,
+    RefNeg = 22,
+    Invalid = 0b11111,
+}
+
+impl From<u8> for Input {
+    fn from(x: u8) -> Self {
+        match x {
+            0 => Input::Ain0,
+            1 => Input::Ain1,
+            2 => Input::Ain2,
+            3 => Input::Ain3,
+            4 => Input::Ain4,
+            17 => Input::TemperaturePos,
+            18 => Input::TemperatureNeg,
+            19 => Input::AnalogSupplyPos,
+            20 => Input::AnalogSupplyNeg,
+            21 => Input::RefPos,
+            22 => Input::RefNeg,
+            _ => Input::Invalid,
+        }
+    }
+}
+
+impl fmt::Display for Input {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        use Input::*;
+
+        match self {
+            Ain0 => "ain0",
+            Ain1 => "ain1",
+            Ain2 => "ain2",
+            Ain3 => "ain3",
+            Ain4 => "ain4",
+            TemperaturePos => "temperature+",
+            TemperatureNeg => "temperature-",
+            AnalogSupplyPos => "analogsupply+",
+            AnalogSupplyNeg => "analogsupply-",
+            RefPos => "ref+",
+            RefNeg => "ref-",
+            _ => "<INVALID>",
+        }.fmt(fmt)
+    }
+}
+
+/// Reference source for ADC conversion
+#[repr(u8)]
+pub enum RefSource {
+    /// External reference
+    External = 0b00,
+    /// Internal 2.5V reference
+    Internal = 0b10,
+    /// AVDD1 − AVSS
+    Avdd1MinusAvss = 0b11,
+    Invalid = 0b01,
+}
+
+impl From<u8> for RefSource {
+    fn from(x: u8) -> Self {
+        match x {
+            0 => RefSource::External,
+            1 => RefSource::Internal,
+            2 => RefSource::Avdd1MinusAvss,
+            _ => RefSource::Invalid,
+        }
+    }
+}
+
+impl fmt::Display for RefSource {
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        use RefSource::*;
+
+        match self {
+            External => "external",
+            Internal => "internal",
+            Avdd1MinusAvss => "avdd1-avss",
+            _ => "<INVALID>",
+        }.fmt(fmt)
+    }
+}
+
+#[derive(Clone, Copy)]
+#[repr(u8)]
+pub enum PostFilter {
+    /// 27 SPS, 47 dB rejection, 36.7 ms settling
+    F27SPS = 0b010,
+    /// 21.25 SPS, 62 dB rejection, 40 ms settling
+    F21SPS = 0b011,
+    /// 20 SPS, 86 dB rejection, 50 ms settling
+    F20SPS = 0b101,
+    /// 16.67 SPS, 92 dB rejection, 60 ms settling
+    F16SPS = 0b110,
+    Invalid = 0b111,
+}
+
+impl PostFilter {
+    pub const VALID_VALUES: &'static [Self] = &[
+        PostFilter::F27SPS,
+        PostFilter::F21SPS,
+        PostFilter::F20SPS,
+        PostFilter::F16SPS,
+    ];
+
+    pub fn closest(rate: f32) -> Option<Self> {
+        /// (x - y).abs()
+        fn d(x: f32, y: f32) -> f32 {
+            if x >= y {
+                x - y
+            } else {
+                y - x
+            }
+        }
+
+        let mut best: Option<(f32, Self)> = None;
+        for value in Self::VALID_VALUES {
+            let error = d(rate, value.output_rate().unwrap());
+            let better = best
+                .map(|(best_error, _)| error < best_error)
+                .unwrap_or(true);
+            if better {
+                best = Some((error, *value));
+            }
+        }
+        best.map(|(_, best)| best)
+    }
+
+    /// Samples per Second
+    pub fn output_rate(&self) -> Option<f32> {
+        match self {
+            PostFilter::F27SPS => Some(27.0),
+            PostFilter::F21SPS => Some(21.25),
+            PostFilter::F20SPS => Some(20.0),
+            PostFilter::F16SPS => Some(16.67),
+            PostFilter::Invalid => None,
+        }
+    }
+}
+
+impl From<u8> for PostFilter {
+    fn from(x: u8) -> Self {
+        match x {
+            0b010 => PostFilter::F27SPS,
+            0b011 => PostFilter::F21SPS,
+            0b101 => PostFilter::F20SPS,
+            0b110 => PostFilter::F16SPS,
+            _ => PostFilter::Invalid,
+        }
+    }
+}
+
+#[repr(u8)]
+pub enum DigitalFilterOrder {
+    Sinc5Sinc1 = 0b00,
+    Sinc3 = 0b11,
+    Invalid = 0b10,
+}
+
+impl From<u8> for DigitalFilterOrder {
+    fn from(x: u8) -> Self {
+        match x {
+            0b00 => DigitalFilterOrder::Sinc5Sinc1,
+            0b11 => DigitalFilterOrder::Sinc3,
+            _ => DigitalFilterOrder::Invalid,
+        }
+    }
+}

src/ad7172/regs.rs

@@ -0,0 +1,260 @@
+use byteorder::{BigEndian, ByteOrder};
+use bit_field::BitField;
+
+use super::*;
+
+pub trait Register {
+    type Data: RegisterData;
+    fn address(&self) -> u8;
+}
+pub trait RegisterData {
+    fn empty() -> Self;
+    fn as_mut(&mut self) -> &mut [u8];
+}
+
+macro_rules! def_reg {
+    ($Reg: ident, $reg: ident, $addr: expr, $size: expr) => {
+        /// AD7172 register
+        pub struct $Reg;
+        impl Register for $Reg {
+            /// Register contents
+            type Data = $reg::Data;
+            /// Register address
+            fn address(&self) -> u8 {
+                $addr
+            }
+        }
+        mod $reg {
+            /// Register contents
+            pub struct Data(pub [u8; $size]);
+            impl super::RegisterData for Data {
+                /// Generate zeroed register contents
+                fn empty() -> Self {
+                    Data([0; $size])
+                }
+                /// Borrow for SPI transfer
+                fn as_mut(&mut self) -> &mut [u8] {
+                    &mut self.0
+                }
+            }
+        }
+    };
+    ($Reg: ident, u8, $reg: ident, $addr: expr, $size: expr) => {
+        pub struct $Reg { pub index: u8, }
+        impl Register for $Reg {
+            type Data = $reg::Data;
+            fn address(&self) -> u8 {
+                $addr + self.index
+            }
+        }
+        mod $reg {
+            pub struct Data(pub [u8; $size]);
+            impl super::RegisterData for Data {
+                fn empty() -> Self {
+                    Data([0; $size])
+                }
+                fn as_mut(&mut self) -> &mut [u8] {
+                    &mut self.0
+                }
+            }
+        }
+    }
+}
+
+macro_rules! reg_bit {
+    ($getter: ident, $byte: expr, $bit: expr, $doc: expr) => {
+        #[allow(unused)]
+        #[doc = $doc]
+        pub fn $getter(&self) -> bool {
+            self.0[$byte].get_bit($bit)
+        }
+    };
+    ($getter: ident, $setter: ident, $byte: expr, $bit: expr, $doc: expr) => {
+        #[allow(unused)]
+        #[doc = $doc]
+        pub fn $getter(&self) -> bool {
+            self.0[$byte].get_bit($bit)
+        }
+        #[allow(unused)]
+        #[doc = $doc]
+        pub fn $setter(&mut self, value: bool) {
+            self.0[$byte].set_bit($bit, value);
+        }
+    };
+}
+
+macro_rules! reg_bits {
+    ($getter: ident, $byte: expr, $bits: expr, $doc: expr) => {
+        #[allow(unused)]
+        #[doc = $doc]
+        pub fn $getter(&self) -> u8 {
+            self.0[$byte].get_bits($bits)
+        }
+    };
+    ($getter: ident, $setter: ident, $byte: expr, $bits: expr, $doc: expr) => {
+        #[allow(unused)]
+        #[doc = $doc]
+        pub fn $getter(&self) -> u8 {
+            self.0[$byte].get_bits($bits)
+        }
+        #[allow(unused)]
+        #[doc = $doc]
+        pub fn $setter(&mut self, value: u8) {
+            self.0[$byte].set_bits($bits, value);
+        }
+    };
+    ($getter: ident, $byte: expr, $bits: expr, $ty: ty, $doc: expr) => {
+        #[allow(unused)]
+        #[doc = $doc]
+        pub fn $getter(&self) -> $ty {
+            self.0[$byte].get_bits($bits) as $ty
+        }
+    };
+    ($getter: ident, $setter: ident, $byte: expr, $bits: expr, $ty: ty, $doc: expr) => {
+        #[allow(unused)]
+        #[doc = $doc]
+        pub fn $getter(&self) -> $ty {
+            self.0[$byte].get_bits($bits).into()
+        }
+        #[allow(unused)]
+        #[doc = $doc]
+        pub fn $setter(&mut self, value: $ty) {
+            self.0[$byte].set_bits($bits, value as u8);
+        }
+    };
+}
+
+def_reg!(Status, status, 0x00, 1);
+impl status::Data {
+    /// Is there new data to read?
+    pub fn ready(&self) -> bool {
+        ! self.not_ready()
+    }
+
+    reg_bit!(not_ready, 0, 7, "No data ready indicator");
+    reg_bits!(channel, 0, 0..=1, "Channel for which data is ready");
+    reg_bit!(adc_error, 0, 6, "ADC error");
+    reg_bit!(crc_error, 0, 5, "SPI CRC error");
+    reg_bit!(reg_error, 0,4, "Register error");
+}
+
+def_reg!(IfMode, if_mode, 0x02, 2);
+impl if_mode::Data {
+    reg_bits!(crc, set_crc, 1, 2..=3, ChecksumMode, "SPI checksum mode");
+}
+
+def_reg!(Data, data, 0x04, 3);
+impl data::Data {
+    pub fn data(&self) -> i32 {
+        let raw =
+            (u32::from(self.0[0]) << 16) |
+            (u32::from(self.0[1]) << 8) |
+            u32::from(self.0[2]);
+        if raw & 0x80_0000 != 0 {
+            ((raw & 0x7F_FFFF) | 0x8000_0000) as i32
+        } else {
+            raw as i32
+        }
+    }
+}
+
+def_reg!(GpioCon, gpio_con, 0x06, 2);
+impl gpio_con::Data {
+    reg_bit!(sync_en, set_sync_en, 0, 3, "Enables the SYNC/ERROR pin as a sync input");
+}
+
+def_reg!(Id, id, 0x07, 2);
+impl id::Data {
+    pub fn id(&self) -> u16 {
+        BigEndian::read_u16(&self.0)
+    }
+}
+
+def_reg!(Channel, u8, channel, 0x10, 2);
+impl channel::Data {
+    reg_bit!(enabled, set_enabled, 0, 7, "Channel enabled");
+    reg_bits!(setup, set_setup, 0, 4..=5, "Setup number");
+
+    /// Which input is connected to positive input of this channel
+    #[allow(unused)]
+    pub fn a_in_pos(&self) -> Input {
+        ((self.0[0].get_bits(0..=1) << 3) |
+         self.0[1].get_bits(5..=7)).into()
+    }
+    /// Set which input is connected to positive input of this channel
+    #[allow(unused)]
+    pub fn set_a_in_pos(&mut self, value: Input) {
+        let value = value as u8;
+        self.0[0].set_bits(0..=1, value >> 3);
+        self.0[1].set_bits(5..=7, value & 0x7);
+    }
+    reg_bits!(a_in_neg, set_a_in_neg, 1, 0..=4, Input,
+              "Which input is connected to negative input of this channel");
+
+    // const PROPS: &'static [Property<Self>] = &[
+    //     Property::named("enable")
+    //         .readable(&|self_: &Self| self_.enabled().into())
+    //         .writebale(&|self_: &mut Self, value| self_.set_enabled(value != 0)),
+    //     Property::named("setup")
+    //         .readable(&|self_: &Self| self_.0[0].get_bits(4..=5).into())
+    //         .writeable(&|self_: &mut Self, value| {
+    //             self_.0[0].set_bits(4..=5, value as u8);
+    //         }),
+    // ];
+
+    // pub fn props() -> &'static [Property<Self>] {
+    //     Self::PROPS
+    // }
+}
+
+def_reg!(SetupCon, u8, setup_con, 0x20, 2);
+impl setup_con::Data {
+    reg_bit!(bipolar, set_bipolar, 0, 4, "Unipolar (`false`) or bipolar (`true`) coded output");
+    reg_bit!(refbuf_pos, set_refbuf_pos, 0, 3, "Enable REF+ input buffer");
+    reg_bit!(refbuf_neg, set_refbuf_neg, 0, 2, "Enable REF- input buffer");
+    reg_bit!(ainbuf_pos, set_ainbuf_pos, 0, 1, "Enable AIN+ input buffer");
+    reg_bit!(ainbuf_neg, set_ainbuf_neg, 0, 0, "Enable AIN- input buffer");
+    reg_bit!(burnout_en, 1, 7, "enables a 10 µA current source on the positive analog input selected and a 10 µA current sink on the negative analog input selected");
+    reg_bits!(ref_sel, set_ref_sel, 1, 4..=5, RefSource, "Select reference source for conversion");
+}
+
+def_reg!(FiltCon, u8, filt_con, 0x28, 2);
+impl filt_con::Data {
+    reg_bit!(sinc3_map, 0, 7, "If set, mapping of filter register changes to directly program the decimation rate of the sinc3 filter");
+    reg_bit!(enh_filt_en, set_enh_filt_en, 0, 3, "Enable postfilters for enhanced 50Hz and 60Hz rejection");
+    reg_bits!(enh_filt, set_enh_filt, 0, 0..=2, PostFilter, "Select postfilters for enhanced 50Hz and 60Hz rejection");
+    reg_bits!(order, set_order, 1, 5..=6, DigitalFilterOrder, "order of the digital filter that processes the modulator data");
+    reg_bits!(odr, set_odr, 1, 0..=4, "Output data rate");
+}
+
+def_reg!(Offset, u8, offset, 0x30, 3);
+impl offset::Data {
+    #[allow(unused)]
+    pub fn offset(&self) -> u32 {
+        (u32::from(self.0[0]) << 16) |
+        (u32::from(self.0[1]) << 8) |
+        u32::from(self.0[2])
+    }
+    #[allow(unused)]
+    pub fn set_offset(&mut self, value: u32) {
+        self.0[0] = (value >> 16) as u8;
+        self.0[1] = (value >> 8) as u8;
+        self.0[2] = value as u8;
+    }
+}
+
+def_reg!(Gain, u8, gain, 0x38, 3);
+impl gain::Data {
+    #[allow(unused)]
+    pub fn gain(&self) -> u32 {
+        (u32::from(self.0[0]) << 16) |
+        (u32::from(self.0[1]) << 8) |
+        u32::from(self.0[2])
+    }
+    #[allow(unused)]
+    pub fn set_gain(&mut self, value: u32) {
+        self.0[0] = (value >> 16) as u8;
+        self.0[1] = (value >> 8) as u8;
+        self.0[2] = value as u8;
+    }
+}

src/adc_input.rs

@@ -1,46 +0,0 @@
-use stm32f4xx_hal::{
-    adc::{
-        Adc,
-        config::*,
-    },
-    gpio::{Analog, gpioa::PA3 as Pin},
-    stm32::ADC1 as ADC,
-};
-
-/// ADC Input
-pub struct AdcInput {
-    /// unused but consumed
-    _pin: Pin<Analog>,
-    adc: Adc<ADC>,
-}
-
-impl AdcInput {
-    /// Configure pin into analog mode
-    pub fn new<MODE>(adc: ADC, pin: Pin<MODE>) -> Self {
-        let pin = pin.into_analog();
-        let adc_config = AdcConfig::default()
-            .scan(Scan::Enabled)
-            .continuous(Continuous::Single)
-            .clock(Clock::Pclk2_div_2);
-        let mut adc = Adc::adc1(adc, true, adc_config);
-
-        adc.configure_channel(&pin, Sequence::One, SampleTime::Cycles_480);
-        
-        AdcInput { _pin: pin, adc }
-    }
-
-    /// Enable the ADC,
-    /// run a conversion
-    /// disable the ADC
-    pub fn read(&mut self) -> u16 {
-        let adc = &mut self.adc;
-        adc.enable();
-        adc.clear_end_of_conversion_flag();
-        adc.start_conversion();
-        let sample = adc.current_sample();
-        let result = adc.sample_to_millivolts(sample);
-        adc.wait_for_conversion_sequence();
-        adc.disable();
-        result
-    }
-}

src/main.rs

@@ -15,7 +15,6 @@ use cortex_m_rt::entry;
 use embedded_hal::watchdog::{WatchdogEnable, Watchdog};
 use stm32f4xx_hal::{
     rcc::RccExt,
-    gpio::GpioExt,
     watchdog::IndependentWatchdog,
     time::U32Ext,
     stm32::{CorePeripherals, Peripherals},
@@ -26,8 +25,8 @@ use smoltcp::{
 };
 
 mod pins;
-mod adc_input;
-use adc_input::AdcInput;
+use pins::Pins;
+mod ad7172;
 mod net;
 mod server;
 use server::Server;
@@ -86,20 +85,11 @@ fn main() -> ! {
     wd.start(1000u32.ms());
     wd.feed();
 
-    let gpioa = dp.GPIOA.split();
-    let gpiob = dp.GPIOB.split();
-    let gpioc = dp.GPIOC.split();
-    let gpiog = dp.GPIOG.split();
+    let pins = Pins::setup(clocks, dp.GPIOA, dp.GPIOB, dp.GPIOC, dp.GPIOG, dp.SPI2);
 
     info!("ADC init");
-    let mut adc_input = AdcInput::new(dp.ADC1, gpioa.pa3);
-
-    info!("Eth setup");
-    pins::setup_ethernet(
-        gpioa.pa1, gpioa.pa2, gpioc.pc1, gpioa.pa7,
-        gpioc.pc4, gpioc.pc5, gpiob.pb11, gpiog.pg13,
-        gpiob.pb13
-    );
+    let mut adc = ad7172::Adc::new(pins.adc_spi, pins.adc_nss).unwrap();
+    adc.set_checksum_mode(ad7172::ChecksumMode::Crc).unwrap();
 
     info!("Timer setup");
     timer::setup(cp.SYST, clocks);
@@ -128,8 +118,8 @@ fn main() -> ! {
 
                 let now = timer::now().0;
                 if now - last_output >= OUTPUT_INTERVAL {
-                    let adc_value = adc_input.read();
-                    writeln!(server, "t={},pa3={}\r", now, adc_value).unwrap();
+                    // let adc_value = adc_input.read();
+                    writeln!(server, "t={},pa3={}\r", now, 0.0 /*adc_value*/).unwrap();
                     last_output = now;
                 }
 

src/pins.rs

@@ -1,16 +1,76 @@
-use stm32f4xx_hal::gpio::{
+use stm32f4xx_hal::{
+    gpio::{
+        AF5, Alternate,
         gpioa::{PA1, PA2, PA7},
-    gpiob::{PB11, PB13},
+        gpiob::{PB10, PB11, PB12, PB13, PB14, PB15},
         gpioc::{PC1, PC4, PC5},
         gpiog::{PG13},
+        GpioExt,
+        Output, PushPull,
         Speed::VeryHigh,
+    },
+    rcc::Clocks,
+    spi::Spi,
+    stm32::{GPIOA, GPIOB, GPIOC, GPIOG, SPI2},
 };
 
-pub fn setup_ethernet<M1, M2, M3, M4, M5, M6, M7, M8, M9>(
+
+/// SPI peripheral used for communication with the ADC
+type AdcSpi = Spi<SPI2, (PB10<Alternate<AF5>>, PB14<Alternate<AF5>>, PB15<Alternate<AF5>>)>;
+
+pub struct Pins {
+    pub adc_spi: AdcSpi,
+    pub adc_nss: PB12<Output<PushPull>>,
+}
+
+impl Pins {
+    /// Setup GPIO pins and configure MCU peripherals
+    pub fn setup(clocks: Clocks, gpioa: GPIOA, gpiob: GPIOB, gpioc: GPIOC, gpiog: GPIOG, spi2: SPI2) -> Self {
+        let gpioa = gpioa.split();
+        let gpiob = gpiob.split();
+        let gpioc = gpioc.split();
+        let gpiog = gpiog.split();
+
+        Self::setup_ethernet(
+            gpioa.pa1, gpioa.pa2, gpioc.pc1, gpioa.pa7,
+            gpioc.pc4, gpioc.pc5, gpiob.pb11, gpiog.pg13,
+            gpiob.pb13
+        );
+        let adc_spi = Self::setup_spi_adc(clocks, spi2, gpiob.pb10, gpiob.pb14, gpiob.pb15);
+        let adc_nss = gpiob.pb12.into_push_pull_output();
+        Pins {
+            adc_spi,
+            adc_nss,
+        }
+    }
+
+    /// Configure the GPIO pins for SPI operation, and initialize SPI
+    fn setup_spi_adc<M1, M2, M3>(
+        clocks: Clocks,
+        spi2: SPI2,
+        sck: PB10<M1>,
+        miso: PB14<M2>,
+        mosi: PB15<M3>,
+    ) -> AdcSpi
+    {
+        let sck = sck.into_alternate_af5();
+        let miso = miso.into_alternate_af5();
+        let mosi = mosi.into_alternate_af5();
+        Spi::spi2(
+            spi2,
+            (sck, miso, mosi),
+            crate::ad7172::SPI_MODE,
+            crate::ad7172::SPI_CLOCK.into(),
+            clocks
+        )
+    }
+
+    /// Configure the GPIO pins for Ethernet operation
+    fn setup_ethernet<M1, M2, M3, M4, M5, M6, M7, M8, M9>(
         pa1: PA1<M1>, pa2: PA2<M2>, pc1: PC1<M3>, pa7: PA7<M4>,
         pc4: PC4<M5>, pc5: PC5<M6>, pb11: PB11<M7>, pg13: PG13<M8>,
         pb13: PB13<M9>
-) {
+    ) {
         // PA1 RMII Reference Clock - SB13 ON
         pa1.into_alternate_af11().set_speed(VeryHigh);
         // PA2 RMII MDIO - SB160 ON
@@ -29,4 +89,5 @@ pub fn setup_ethernet<M1, M2, M3, M4, M5, M6, M7, M8, M9>(
         pg13.into_alternate_af11().set_speed(VeryHigh);
         // PB13 RMII TXD1 I2S_A_CK JP7 ON
         pb13.into_alternate_af11().set_speed(VeryHigh);
+    }
 }