ld: Use Timer IRQ to ramp up/down output current

- Fixes possible watchdog timeout
- Improves ethernet response time & thermostat Pid update interval consistency

src/device/boot.rs

@@ -8,6 +8,7 @@ use crate::net::net::ServerHandle;
 use stm32_eth;
 use fugit::ExtU32;
 use log::{info, debug};
+use stm32f4xx_hal::timer::TimerExt;
 use stm32f4xx_hal::{
     pac::{CorePeripherals, Peripherals},
     rcc::RccExt,
@@ -71,7 +72,7 @@ pub fn bootup(
 
     debug!("Setting up Laser Driver");
     let current_source = LdCtrl::new(current_source_phy);
-    let mut laser = LdDrive::new(current_source, perif.ADC2, pd_mon_phy);
+    let mut laser = LdDrive::new(current_source, perif.ADC2, perif.TIM2.counter(&clocks), pd_mon_phy);
     laser.setup();
     laser.ld_open();
     laser.set_ld_drive_current_limit(ElectricCurrent::new::<ampere>(0.2));

src/laser_diode/laser_diode.rs

@@ -1,9 +1,11 @@
 use miniconf::Tree;
-use stm32f4xx_hal::pac::ADC2;
+use stm32f4xx_hal::timer::CounterUs;
+use stm32f4xx_hal::pac::{ADC2, TIM2};
 use uom::si::electric_current::ampere;
 use crate::laser_diode::ld_ctrl::{LdCtrl, Impedance};
 use crate::laser_diode::ld_pwr_exc_protector::{LdPwrExcProtector, self};
 use crate::laser_diode::pd_responsitivity;
+use crate::laser_diode::ld_current_out_ctrl_timer::LdCurrentOutCtrlTimer;
 use core::marker::PhantomData;
 use crate::device::sys_timer::sleep;
 use serde::{Deserialize, Serialize};
@@ -12,9 +14,7 @@ use uom::si::{
     electric_current::milliampere,
     f64::{ElectricPotential, ElectricCurrent, Power},
 };
-use num_traits::Float;
+use uom::{si::{ISQ, SI, Quantity}, typenum::*};
-
-use uom::{si::{ISQ, SI, Quantity, ratio::ratio}, typenum::*};
 
 // Volt / Ampere
 pub type TransimpedanceUnit = Quantity<ISQ<P2, P1, N3, N2, Z0, Z0, Z0>, SI<f64>, f64>;
@@ -40,14 +40,6 @@ impl Settings{
         units: PhantomData,
         value: 10.0 / 0.75,
     };
-
-    const LD_CURRENT_STEP_SIZE: ElectricCurrent = ElectricCurrent {
-        dimension: PhantomData,
-        units: PhantomData,
-        value: 0.0001,
-    };
-
-    const LD_CURRENT_TIME_STEP_MS: u32 = 1;
 }
 
 #[derive(Clone, Debug, Tree)]
@@ -84,8 +76,9 @@ pub struct LdDrive{
 }
 
 impl LdDrive{
-    pub fn new(current_source: LdCtrl, pins_adc: ADC2, phy: ld_pwr_exc_protector::LdPwrExcProtectorPhy)-> Self {
+    pub fn new(current_source: LdCtrl, pins_adc: ADC2, tim2: CounterUs<TIM2>, phy: ld_pwr_exc_protector::LdPwrExcProtectorPhy)-> Self {
         LdPwrExcProtector::setup(pins_adc, phy);
+        LdCurrentOutCtrlTimer::setup(tim2);
         
         LdDrive {
             ctrl: current_source,
@@ -95,7 +88,8 @@ impl LdDrive{
 
     pub fn setup(&mut self) {
         LdPwrExcProtector::pwr_off();
-        self.ld_set_i(ElectricCurrent::new::<milliampere>(0.0));
+        self.ctrl.set_i(ElectricCurrent::new::<milliampere>(0.0), Settings::LD_DRIVE_TRANSIMPEDANCE, Settings::DAC_OUT_V_MAX);
+        LdCurrentOutCtrlTimer::reset();
         self.ld_short();
     }
 
@@ -117,6 +111,7 @@ impl LdDrive{
 
     pub fn power_up(&mut self){            
         let _ = self.ctrl.set_i(ElectricCurrent::new::<milliampere>(0.0), Settings::LD_DRIVE_TRANSIMPEDANCE, Settings::DAC_OUT_V_MAX);
+        LdCurrentOutCtrlTimer::reset();
         LdPwrExcProtector::pwr_on_and_arm_protection();
         // Wait for LD Power Supply to start up before driving current to laser diode
         sleep(30);
@@ -135,28 +130,22 @@ impl LdDrive{
         self.settings.pd_responsitivity.get_ld_pwr_from_ld_i(LdPwrExcProtector::get_status().v * Settings::PD_MON_TRANSCONDUCTANCE) 
     }
 
-    // Ramping up or down laser diode current according to preset current step size and time step.
+    pub fn ld_set_i(&mut self, i: ElectricCurrent){
-    pub fn ld_set_i(&mut self, i: ElectricCurrent) -> ElectricCurrent {
+        LdCurrentOutCtrlTimer::set_target_i_and_listen_irq(i, self.settings.ld_drive_current);
-        let mut prev_i_set = self.settings.ld_drive_current;
-        let final_i_set = i.min(self.settings.ld_drive_current_limit).max(ElectricCurrent::new::<ampere>(0.0));
-        
-        let num_of_step = ((final_i_set - prev_i_set)/Settings::LD_CURRENT_STEP_SIZE).get::<ratio>().floor() as i32;
-
-        let current_step = if num_of_step.is_positive() {
-            Settings::LD_CURRENT_STEP_SIZE
-        } else { 
-            -Settings::LD_CURRENT_STEP_SIZE 
-        };
-        
-        for _ in 0..num_of_step.abs() {
-            prev_i_set = prev_i_set + current_step;
-            let _ = self.ctrl.set_i(prev_i_set, Settings::LD_DRIVE_TRANSIMPEDANCE, Settings::DAC_OUT_V_MAX);
-            sleep(Settings::LD_CURRENT_TIME_STEP_MS);
     }
-        let prev_i_set = self.ctrl.set_i(final_i_set, Settings::LD_DRIVE_TRANSIMPEDANCE, Settings::DAC_OUT_V_MAX);
 
-        self.settings.ld_drive_current = prev_i_set;
+    pub fn poll_and_update_output_current(&mut self) -> ElectricCurrent {
-        prev_i_set
+        match LdCurrentOutCtrlTimer::get_irq_status() {
+            Some(i_set) => {
+                let i_set = self.ctrl.set_i(i_set, Settings::LD_DRIVE_TRANSIMPEDANCE, Settings::DAC_OUT_V_MAX);
+                self.settings.ld_drive_current = i_set;
+                LdCurrentOutCtrlTimer::clear_alarm_and_resume_listening();
+                i_set
+            }
+            None => {
+                ElectricCurrent::new::<ampere>(0.0)
+            }
+        }
     }
 
     // Set the calibrated VDDA value obtained from ADC1 calibration

src/laser_diode/ld_current_out_ctrl_timer.rs

@@ -0,0 +1,120 @@
+use stm32f4xx_hal::timer::{CounterUs, Event};
+use stm32f4xx_hal::pac::{interrupt, Interrupt, TIM2};
+use uom::si::{f64::ElectricCurrent, electric_current::ampere};
+use fugit::{TimerDurationU32, KilohertzU32};
+use core::marker::PhantomData;
+
+pub struct LdCurrentOutCtrlTimer {
+    target_i: ElectricCurrent,
+    now_i: ElectricCurrent,
+    timer: CounterUs<TIM2>,
+    timeout: bool,
+}
+static mut LD_CURRENT_OUT_CTRL_TIMER: Option<LdCurrentOutCtrlTimer> = None;
+
+/// This timer notifies the main loop to set the correct output current so that ld output current can ramp up/down slowly.
+///     The current output slope is guaranteed to be larger but not necessarily equal to than the preset value.
+impl LdCurrentOutCtrlTimer {
+    const TIME_STEP_MS: TimerDurationU32<1000000> = TimerDurationU32::from_rate(KilohertzU32::from_raw(1));
+    const STEP_SIZE: ElectricCurrent = ElectricCurrent {
+        dimension: PhantomData,
+        units: PhantomData,
+        value: 0.0001,
+    };
+
+    pub fn setup(mut tim2: CounterUs<TIM2>) {
+        tim2.start(LdCurrentOutCtrlTimer::TIME_STEP_MS).unwrap();
+        unsafe {
+            cortex_m::peripheral::NVIC::unmask(Interrupt::TIM2);
+        }
+        unsafe {
+            LD_CURRENT_OUT_CTRL_TIMER = Some(
+                LdCurrentOutCtrlTimer {
+                    target_i: ElectricCurrent::new::<ampere>(0.0),
+                    now_i: ElectricCurrent::new::<ampere>(0.0),
+                    timer: tim2,
+                    timeout: false
+                }
+            );
+        }
+    }
+
+    fn get() -> Option<&'static mut Self> {
+        unsafe { LD_CURRENT_OUT_CTRL_TIMER.as_mut() }
+    }
+
+    pub fn reset() {
+        if let Some(ref mut ld_current_out_ctrl_timer ) = LdCurrentOutCtrlTimer::get() {
+            ld_current_out_ctrl_timer.target_i = ElectricCurrent::new::<ampere>(0.0);
+            ld_current_out_ctrl_timer.now_i = ElectricCurrent::new::<ampere>(0.0);
+            ld_current_out_ctrl_timer.timeout = false;
+            ld_current_out_ctrl_timer.timer.unlisten(Event::Update);
+        }
+    }
+
+    pub fn set_target_i_and_listen_irq(target: ElectricCurrent, now: ElectricCurrent) {
+        if let Some(ref mut ld_current_out_ctrl_timer ) = LdCurrentOutCtrlTimer::get() {
+            cortex_m::interrupt::free(|_| {
+                    ld_current_out_ctrl_timer.target_i = target;
+                    ld_current_out_ctrl_timer.now_i = now;
+                    ld_current_out_ctrl_timer.timer.listen(Event::Update);
+                }
+            )
+        }
+    }
+
+    pub fn set_alarm() {
+        if let Some(ref mut ld_current_out_ctrl_timer ) = LdCurrentOutCtrlTimer::get() {
+            ld_current_out_ctrl_timer.timeout = true;
+        }
+    }
+    pub fn clear_alarm_and_resume_listening() {
+        if let Some(ref mut ld_current_out_ctrl_timer ) = LdCurrentOutCtrlTimer::get() {
+            ld_current_out_ctrl_timer.timeout = false;
+            ld_current_out_ctrl_timer.timer.listen(Event::Update);
+        }
+    }
+    pub fn get_irq_status() -> Option<ElectricCurrent> {
+        if let Some(ref mut ld_current_out_ctrl_timer ) = LdCurrentOutCtrlTimer::get() {
+            if ld_current_out_ctrl_timer.timeout {
+                return Some(ld_current_out_ctrl_timer.now_i);
+            }
+        }
+        None
+    }
+
+    pub fn clear_irq_flag() {
+        if let Some(ref mut ld_current_out_ctrl_timer ) = LdCurrentOutCtrlTimer::get() {
+            ld_current_out_ctrl_timer.timer.clear_interrupt(Event::Update);
+        }
+    }
+
+    pub fn update_next_i_set() -> bool {
+        if let Some(ref mut ld_current_out_ctrl_timer ) = LdCurrentOutCtrlTimer::get() {
+            let update = ld_current_out_ctrl_timer.now_i != ld_current_out_ctrl_timer.target_i;
+            if ld_current_out_ctrl_timer.target_i > ld_current_out_ctrl_timer.now_i {
+                ld_current_out_ctrl_timer.now_i = (ld_current_out_ctrl_timer.now_i + LdCurrentOutCtrlTimer::STEP_SIZE).min(ld_current_out_ctrl_timer.target_i);
+            }
+            else {
+                ld_current_out_ctrl_timer.now_i = (ld_current_out_ctrl_timer.now_i - LdCurrentOutCtrlTimer::STEP_SIZE).max(ld_current_out_ctrl_timer.target_i);
+            }
+            return update
+        }
+        false
+    }
+
+    pub fn stop_listening() {
+        if let Some(ref mut ld_current_out_ctrl_timer ) = LdCurrentOutCtrlTimer::get() {
+            ld_current_out_ctrl_timer.timer.unlisten(Event::Update);
+        }
+    }
+}
+
+#[interrupt]
+fn TIM2(){
+    if LdCurrentOutCtrlTimer::update_next_i_set() {
+        LdCurrentOutCtrlTimer::set_alarm();
+    }
+    LdCurrentOutCtrlTimer::stop_listening();
+    LdCurrentOutCtrlTimer::clear_irq_flag();
+}

src/laser_diode/mod.rs

@@ -3,3 +3,4 @@ pub mod max5719;
 pub mod laser_diode;
 pub mod pd_responsitivity;
 pub mod ld_pwr_exc_protector;
+pub mod ld_current_out_ctrl_timer;

src/main.rs

@@ -94,6 +94,8 @@ fn main() -> ! {
         if !should_reset {
             let mut eth_is_pending = false;
         
+            laser.poll_and_update_output_current();
+            
             if thermostat.poll_adc_and_update_pid() {
                 info!("curr_dac_vfb: {:?}", volt_fmt.with(thermostat.get_dac_vfb()));
                 info!("curr_vref: {:?}", volt_fmt.with(thermostat.get_vref()));