current_source: add driver to read pd voltage

src/laser_diode/current_sources.rs

@@ -11,6 +11,7 @@ use stm32f4xx_hal::{
 
 use uom::si::{
     ratio::ratio,
+    electric_potential::millivolt,
     f64::{ElectricPotential, ElectricCurrent},
 };
 
@@ -89,6 +90,15 @@ impl CurrentSource {
         self.phy.current_source_short_pin.set_high();
     }
 
+    pub fn get_pd_mon_v(&mut self) -> ElectricPotential{
+        let sample = self.pins_adc.convert(
+            &self.phy.pd_mon_pin,
+            stm32f4xx_hal::adc::config::SampleTime::Cycles_480,
+        );
+        let mv = self.pins_adc.sample_to_millivolts(sample as u16);
+        ElectricPotential::new::<millivolt>(mv as f64)
+    }
+
     pub fn set_dac(&mut self, voltage: ElectricPotential, dac_out_v_max: ElectricPotential) -> ElectricPotential {
         let value = ((voltage / dac_out_v_max).get::<ratio>()
             * (max5719::MAX_VALUE as f64)) as u32;