run at max clock, delay before deep sleep, document weird behaviours

to prevent the back and forth after I forget.

humidity-monitor-c6/src/main.rs

@@ -56,7 +56,13 @@ fn main() -> ! {
 
     let peripherals = Peripherals::take();
     let system = SystemControl::new(peripherals.SYSTEM);
-    let clocks = ClockControl::boot_defaults(system.clock_control).freeze();
+
+    // Ideally we would like to run at minimum clock (boot_defaults) but there
+    // appear to be issues with low clock speeds. Like getting stuck without
+    // serial comms to reflash the program, or getting weird readings on the ADC
+    // after a few iterations of deep sleep.
+    let clocks = ClockControl::max(system.clock_control).freeze();
+
     let io = Io::new(peripherals.GPIO, peripherals.IO_MUX);
 
     let mut rtc = Rtc::new(peripherals.LPWR, None);
@@ -80,20 +86,13 @@ fn main() -> ! {
     let mut warmup = || delay.delay_millis(HYGROMETER_WARMUP);
     let mut read_adc = || hygrometer_adc1.read_oneshot(hygrometer_adc1_pin).unwrap();
 
-    // loop {
-    //     let summary = sample::perform_sampling(
-    //         255,
-    //         &mut toggle,
-    //         &mut warmup,
-    //         &mut read_adc,
-    //         Hygrometer::HW390,
-    //     );
-    //     println!("avg: {} min: {} max: {}", summary.avg, summary.min, summary.max);
-    //     delay.delay_millis(1000);
-    // }
-
-    let summary =
-        sample::perform_sampling(HYGROMETER_SAMPLES, &mut toggle, &mut warmup, &mut read_adc, Hygrometer::HW390);
+    let summary = sample::perform_sampling(
+        HYGROMETER_SAMPLES,
+        &mut toggle,
+        &mut warmup,
+        &mut read_adc,
+        Hygrometer::HW390,
+    );
 
     unsafe { SAMPLE_HISTORY.store(summary) };
 
@@ -141,5 +140,11 @@ fn main() -> ! {
     pulse!(alarm, delay, 100);
 
     let timer = TimerWakeupSource::new(Duration::from_millis(MEASURE_DELAY));
+
+    // Not sure if this delay is needed, I certainly notice weird behaviours when
+    // going to sleep and waking up. Such as ADC readings working well for the first
+    // two or three cycles, and then suddenly become uncalibrated.
+    delay.delay_millis(1000);
+
     rtc.sleep_deep(&[&timer], delay);
 }