control segment brightness; test pattern

src/timer.rs

@@ -13,55 +13,51 @@ const fn us_to_ticks(us: u32) -> u32 {
     TIMER_FREQ * us / 1_000_000
 }
 
-// Sets up timer to rise two interrupts:
-// 1. TIMER0_COMPA - segment_switch_us - time in μs to switch to next segment
-// 2. TIMER0_COMPB - segment_on_us - time in μs to keep segment LEDs on
-pub fn segment_timer_init(tc0: TC0, segment_switch_us: u32, segment_on_us: u32) {
-    // 16_000_000 / 64 * 1000 / 1_000_000 => 250
-    let ocra = us_to_ticks(segment_switch_us);
-    let ocrb = us_to_ticks(segment_on_us);
-    assert!(
-        ocra > ocrb + BUFFER_TICKS,
-        "segment_on_us cannot be longer than segment_switch_us - buffer"
-    );
+// Timer 0 (8bit)
+pub struct SegmentTimer(TC0);
 
-    // Use CTC mode: reset counter when matches compare value
-    tc0.tccr0a.write(|w| w.wgm0().ctc());
-    // Set the compare value for TOP (reset)
-    tc0.ocr0a.write(|w| {
-        w.bits(
-            ocra.try_into()
-                .expect("timer init segment_switch_us out of rage"),
-        )
-    });
-    // Set the compare value for B match
-    tc0.ocr0b.write(|w| {
-        w.bits(
-            ocrb.try_into()
-                .expect("timer init segment_on_us out of rage"),
-        )
-    });
-    // Slow down the timer (CLK / prescale)
-    tc0.tccr0b.write(|w| w.cs0().prescale_64());
-    // Raise interrupt on TOP (reset)
-    // Raise interrupt on B match
-    tc0.timsk0
-        .write(|w| w.ocie0a().set_bit().ocie0b().set_bit());
-}
+impl SegmentTimer {
+    // Sets up timer to rise interrupts:
+    // 1. TIMER0_COMPA - segment_switch_us - time in μs to switch to next segment
+    // 2. TIMER0_COMPB - set by set_segment_on_time to keep segment LEDs on
+    pub fn init(tc0: TC0, segment_switch_us: u32) -> SegmentTimer {
+        // 16_000_000 / 64 * 1000 / 1_000_000 => 250
+        let ocra = us_to_ticks(segment_switch_us);
 
-// Set for how long the segment LEDs should be on in μs
-pub fn set_segment_on_time(tc0: TC0, segment_on_us: u32) {
-    let ocra = tc0.ocr0a.read().bits();
-    let ocrb = us_to_ticks(segment_on_us);
-    assert!(
-        ocra as u32 > ocrb + BUFFER_TICKS,
-        "segment_on_us cannot be longer than segment_switch_us - buffer"
-    );
-    // Set the compare value for B match
-    tc0.ocr0b.write(|w| {
-        w.bits(
-            ocrb.try_into()
-                .expect("timer init segment_on_us out of rage"),
-        )
-    });
+        // Use CTC mode: reset counter when matches compare value
+        tc0.tccr0a.write(|w| w.wgm0().ctc());
+        // Set the compare value for TOP (reset)
+        tc0.ocr0a.write(|w| {
+            w.bits(
+                ocra.try_into()
+                    .expect("timer init segment_switch_us out of rage"),
+            )
+        });
+        // Slow down the timer (CLK / prescale)
+        tc0.tccr0b.write(|w| w.cs0().prescale_64());
+        // Raise interrupt on TOP (reset)
+        // Raise interrupt on B match
+        tc0.timsk0
+            .write(|w| w.ocie0a().set_bit().ocie0b().set_bit());
+
+        SegmentTimer(tc0)
+    }
+
+    // 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) {
+        let ocra = self.0.ocr0a.read().bits();
+        let ocrb = us_to_ticks(segment_on_us);
+        assert!(
+            ocra as u32 > ocrb + BUFFER_TICKS,
+            "segment_on_us cannot be longer than segment_switch_us - buffer"
+        );
+        // Set the compare value for B match
+        self.0.ocr0b.write(|w| {
+            w.bits(
+                ocrb.try_into()
+                    .expect("timer init segment_on_us out of rage"),
+            )
+        });
+    }
 }