ledmatrix: Sleep after 60s timeout

Signed-off-by: Daniel Schaefer <dhs@frame.work>

Author: JohnAZoidberg

ledmatrix/README.md

@@ -204,9 +204,12 @@ What can change the sleep state
   - USB Suspend
 - Software Triggers
   - Sleep/Wake Command via USB Serial
+  - Idle timer
 
 Both of the hardware triggers change the sleep state if the transition from one state to another.
 For example, if USB suspends, the LED matrix turns off. If it resumes, the LEDs come back on.
 Same for the `SLEEP#` pin.
 
 The sleep/wake command always changes the state. But it can't be received when USB is suspended.
+
+The idle timer will send the device to sleep after a configured timeout.

ledmatrix/src/main.rs

@@ -33,6 +33,10 @@ const SLEEP_MODE: SleepMode = SleepMode::Fading;
 
 const STARTUP_ANIMATION: bool = true;
 
+/// Go to sleep after 60s awake
+const SLEEP_TIMEOUT: u64 = 60_000_000;
+
+/// List maximum current as 500mA in the USB descriptor
 const MAX_CURRENT: usize = 500;
 
 /// Maximum brightness out of 255
@@ -232,8 +236,9 @@ fn main() -> ! {
     fill_grid_pixels(&state, &mut matrix);
 
     let timer = Timer::new(pac.TIMER, &mut pac.RESETS);
-    let mut prev_timer = timer.get_counter().ticks();
+    let mut animation_timer = timer.get_counter().ticks();
     let mut game_timer = timer.get_counter().ticks();
+    let mut sleep_timer = timer.get_counter().ticks();
 
     let mut startup_percentage = Some(0);
     if !STARTUP_ANIMATION {
@@ -286,6 +291,16 @@ fn main() -> ! {
         }
         last_usb_suspended = usb_suspended;
 
+        // Go to sleep after the timer has run out
+        if timer.get_counter().ticks() > sleep_timer + SLEEP_TIMEOUT {
+            sleeping = true;
+        }
+        // Constantly resetting timer during sleep is same as reset it once on waking up.
+        // This means the timer ends up counting the time spent awake.
+        if sleeping {
+            sleep_timer = timer.get_counter().ticks();
+        }
+
         handle_sleep(
             sleeping,
             &mut state,
@@ -295,7 +310,7 @@ fn main() -> ! {
         );
 
         // Handle period display updates. Don't do it too often
-        let render_again = timer.get_counter().ticks() > prev_timer + state.animation_period;
+        let render_again = timer.get_counter().ticks() > animation_timer + state.animation_period;
         if matches!(state.sleeping, SleepState::Awake) && render_again {
             // On startup slowly turn the screen on - it's a pretty effect :)
             match startup_percentage {
@@ -312,7 +327,7 @@ fn main() -> ! {
                     state.grid.0[x].rotate_right(1);
                 }
             }
-            prev_timer = timer.get_counter().ticks();
+            animation_timer = timer.get_counter().ticks();
         }
 
         // Check for new data