linear dimming

src/display.rs

@@ -97,6 +97,10 @@ impl Brightness {
         self.0
     }
 
+    pub fn dimm(self, dimming: u8) -> Brightness {
+        Brightness(self.0.saturating_sub(dimming))
+    }
+
     // Scales brightness (0-255) to range between IO_SEGMENT_ON_MIN_US and IO_SEGMENT_ON_MAX_US
     pub fn scale_brightness(self) -> u32 {
         // Using >> to avoid 32bit division which take ~576 cycles
@@ -112,8 +116,8 @@ impl Segment {
         Segment(0, Brightness::full())
     }
 
-    pub fn brightness(&mut self, b: u8) -> &mut Self {
-        self.1 = Brightness(b);
+    pub fn brightness(&mut self, b: Brightness) -> &mut Self {
+        self.1 = b;
         self
     }
 

src/main.rs

@@ -50,6 +50,12 @@ pub const IO_SEGMENT_RATE_US: u32 = 1000; // Time in μs between segment updates
 pub const IO_SEGMENT_ON_MIN_US: u32 = 80; // How long in μs to hold segment LEDs on (dark)
 pub const IO_SEGMENT_ON_MAX_US: u32 = 700; // How long in μs to hold segment LEDs on (bright)
 
+// Dimming
+pub const DISPLAY_FPS: u16 = (1_000_000 / (IO_SEGMENT_RATE_US * DISPLAY_SEGMENTS as u32)) as u16;
+pub const DISPLAY_DIMM_FRAMES: u16 = DISPLAY_FPS * 10; // How many frames of inactivity before dimming
+pub const DISPLAY_DIMM_SPEED: u8 = 4; // Dimm by amount every frame when sleeping
+pub const DISPLAY_UNDIMM_SPEED: u8 = 16; // Brighten by amount every frame when not sleeping
+
 // Calculator setup
 pub const STACK_DEPTH: usize = 7;
 type Calc = StackCalc<f32, STACK_DEPTH, 5, u8>;
@@ -85,8 +91,7 @@ unsafe fn TIMER0_COMPA() {
         access_global(&IO_LOOP, cs, |io_loop| {
             access_global(&SEGMENT_TIMER, cs, |st| {
                 let brightness = io_loop.display_on();
-                let elapsed = st.segment_on_time(brightness.scale_brightness());
-                io_loop.frame_data = Some((elapsed, brightness.unwrap()));
+                st.segment_on_time(brightness.scale_brightness());
             });
         });
     });
@@ -116,7 +121,8 @@ pub struct IOLoop {
     keyboard: Keyboard,
     readount: Option<KeyReadout>,
     debounce: Debounce,
-    frame_data: Option<(u8, u8)>,
+    sleep_timer: u16,
+    dimming: u8,
 }
 
 impl IOLoop {
@@ -130,7 +136,8 @@ impl IOLoop {
             keyboard,
             readount: None,
             debounce: Default::default(),
-            frame_data: None,
+            sleep_timer: 0,
+            dimming: u8::MAX,
         }
     }
 
@@ -154,19 +161,42 @@ impl IOLoop {
             // Start from first segment
             self.index = 0;
 
-            // Full keyboard scan complete, debounce and return result
-            self.debounce.input(self.readount.take())
+            // Full keyboard scan complete, debounce
+            let key = self.debounce.input(self.readount.take());
+
+            // Reset or advance sleep timer
+            if key.is_some() {
+                self.sleep_timer = 0;
+            } else {
+                self.sleep_timer = self.sleep_timer.saturating_add(1);
+            }
+
+            if self.is_sleep() {
+                self.dimming = self.dimming.saturating_add(DISPLAY_DIMM_SPEED);
+            } else {
+                self.dimming = self.dimming.saturating_sub(DISPLAY_UNDIMM_SPEED);
+            }
+
+            key
         } else {
             None
         }
     }
 
+    pub fn is_sleep(&self) -> bool {
+        self.sleep_timer >= DISPLAY_DIMM_FRAMES
+    }
+
+    pub fn dimming(&self) -> u8 {
+        self.dimming
+    }
+
     pub fn display_on(&mut self) -> Brightness {
         self.select_off();
         let segment = self.dispaly[self.index];
         let brighness = segment.apply(&mut self.segment_pins);
         self.select_on();
-        brighness
+        brighness.dimm(self.dimming)
     }
 
     pub fn display_off(&mut self) {
@@ -185,10 +215,6 @@ impl IOLoop {
     pub fn frame(&self) -> (u16, usize) {
         (self.frame, self.index)
     }
-
-    pub fn frame_data(&self) -> Option<(u8, u8)> {
-        self.frame_data
-    }
 }
 
 #[derive(uDebug)]
@@ -534,7 +560,6 @@ fn main() -> ! {
     let mut display = DispalyState::default();
     number_input.show(&mut display);
 
-    let mut frame_data_index: usize = 0;
     let mut calc = Calc::default();
     let mut state = State {
         transient: TransientState::Done,
@@ -566,12 +591,6 @@ fn main() -> ! {
                     state.calculator
                 )
                 .ok();
-                match key {
-                    KeyPress::Num(n) => {
-                        frame_data_index = n as usize;
-                    }
-                    _ => (),
-                }
                 match state.calculator.on_key(key, &mut number_input, &mut calc) {
                     Ok(new_state) => state.calculator = new_state,
                     Err(err) => {
@@ -618,24 +637,16 @@ fn main() -> ! {
                     .take(calc.len())
                 {
                     seg.dp();
-                }
-                for (no, seg) in display.slice(0, DISPLAY_SEGMENTS).iter_mut().enumerate() {
-                    seg.brightness(
-                        (no * (Brightness::full().unwrap() as usize) / DISPLAY_SEGMENTS) as u8,
-                    );
+                    seg.brightness(Brightness::full());
                 }
             }
             TransientState::Err { .. } => display.error(),
         }
 
-        let ((frame, index), frame_data) = avr_device::interrupt::free(|cs| {
+        avr_device::interrupt::free(|cs| {
             access_global(&IO_LOOP, cs, |io_loop| {
                 io_loop.update_display(&display);
-                (io_loop.frame(), io_loop.frame_data())
             })
         });
-        if frame % 64 == 0 && index == frame_data_index {
-            ufmt::uwriteln!(&mut serial, "[{}, {}] {:?}", frame, index, frame_data).ok();
-        }
     }
 }

src/timer.rs

@@ -43,13 +43,12 @@ impl SegmentTimer {
 
     // Set for how long the segment LEDs should be on in μs
     // Controls TIMER0_COMPB interrupt time after TIMER0_COMPA
-    pub fn segment_on_time(&mut self, segment_on_us: u32) -> u8 {
+    pub fn segment_on_time(&mut self, segment_on_us: u32) {
         let delay: u8 = us_to_ticks(segment_on_us)
             .try_into()
             .expect("timer init segment_on_us out of rage");
         let elapsed = self.timer.tcnt0.read().bits();
         // Set the compare value for B match
         self.timer.ocr0b.write(|w| w.bits(elapsed + delay));
-        return elapsed;
     }
 }