From 9381feec1bd9a438a5bbc037314b892a758f1f3e Mon Sep 17 00:00:00 2001
From: atse <atse@m-labs.hk>
Date: Fri, 16 Aug 2024 16:26:01 +0800
Subject: [PATCH] Constants uom

---
 src/ad7172/adc.rs    | 14 ++++++++------
 src/channel_state.rs | 20 ++++++++++++++------
 src/channels.rs      | 11 +++++++----
 3 files changed, 29 insertions(+), 16 deletions(-)

diff --git a/src/ad7172/adc.rs b/src/ad7172/adc.rs
index 68ebab3..f81627b 100644
--- a/src/ad7172/adc.rs
+++ b/src/ad7172/adc.rs
@@ -1,13 +1,11 @@
+use core::marker::PhantomData;
 use core::fmt;
 use log::{info, warn};
 use stm32f4xx_hal::hal::{
     blocking::spi::Transfer,
     digital::v2::OutputPin,
 };
-use uom::si::{
-    f64::ElectricPotential,
-    electric_potential::volt,
-};
+use uom::si::f64::ElectricPotential;
 use super::{
     regs::{self, Register, RegisterData},
     checksum::{ChecksumMode, Checksum},
@@ -270,7 +268,11 @@ impl ChannelCalibration {
         let data = data + (self.offset as i32 - 0x80_0000) as f64;
         let data = data / (2 << 23) as f64;
 
-        const V_REF: f64 = 3.3;
-        ElectricPotential::new::<volt>(data * V_REF / 0.75)
+        const V_REF: ElectricPotential = ElectricPotential {
+            dimension: PhantomData,
+            units: PhantomData,
+            value: 3.3,
+        };
+        data * V_REF / 0.75
     }
 }
diff --git a/src/channel_state.rs b/src/channel_state.rs
index 4820131..664848d 100644
--- a/src/channel_state.rs
+++ b/src/channel_state.rs
@@ -1,3 +1,5 @@
+use core::marker::PhantomData;
+
 use smoltcp::time::{Duration, Instant};
 use uom::si::{
     f64::{
@@ -9,7 +11,6 @@ use uom::si::{
     },
     electric_potential::volt,
     electric_current::ampere,
-    electrical_resistance::ohm,
     thermodynamic_temperature::degree_celsius,
     time::millisecond,
 };
@@ -20,8 +21,16 @@ use crate::{
     command_parser::CenterPoint,
 };
 
-const R_INNER: f64 = 2.0 * 5100.0;
-const VREF_SENS: f64 = 3.3 / 2.0;
+const R_INNER: ElectricalResistance = ElectricalResistance {
+    dimension: PhantomData,
+    units: PhantomData,
+    value: 2.0 * 5100.0,
+};
+const VREF_SENS: ElectricPotential = ElectricPotential {
+    dimension: PhantomData,
+    units: PhantomData,
+    value: 3.3 / 2.0,
+};
 
 pub struct ChannelState {
     pub adc_data: Option<u32>,
@@ -87,10 +96,9 @@ impl ChannelState {
 
     /// Get `SENS[01]` input resistance
     pub fn get_sens(&self) -> Option<ElectricalResistance> {
-        let r_inner = ElectricalResistance::new::<ohm>(R_INNER);
-        let vref = ElectricPotential::new::<volt>(VREF_SENS);
+        let vref = VREF_SENS;
         let adc_input = self.get_adc()?;
-        let r = r_inner * adc_input / (vref - adc_input);
+        let r = R_INNER * adc_input / (vref - adc_input);
         Some(r)
     }
 
diff --git a/src/channels.rs b/src/channels.rs
index a428dd1..42d1011 100644
--- a/src/channels.rs
+++ b/src/channels.rs
@@ -31,7 +31,11 @@ pub enum PinsAdcReadTarget {
 }
 
 pub const CHANNELS: usize = 2;
-pub const R_SENSE: f64 = 0.05;
+pub const R_SENSE: ElectricalResistance = ElectricalResistance {
+    dimension: PhantomData,
+    units: PhantomData,
+    value: 0.05,
+};
 
 // From design specs
 pub const MAX_TEC_I: ElectricCurrent = ElectricCurrent {
@@ -159,10 +163,9 @@ impl Channels {
             _ => unreachable!(),
         };
         let center_point = vref_meas;
-        let r_sense = ElectricalResistance::new::<ohm>(R_SENSE);
-        let voltage = i_set * 10.0 * r_sense + center_point;
+        let voltage = i_set * 10.0 * R_SENSE + center_point;
         let voltage = self.set_dac(channel, voltage);
-        let i_set = (voltage - center_point) / (10.0 * r_sense);
+        let i_set = (voltage - center_point) / (10.0 * R_SENSE);
         self.channel_state(channel).i_set = i_set;
         i_set
     }