using iterator for scanning

src/main.rs

@@ -2,10 +2,17 @@
 #![no_main]
 
 use arduino_hal::{
-    adc::channel::{ADC6, ADC7},
-    hal::port::{
-        PB0, PB1, PB2, PB3, PB4, PC0, PC1, PC2, PC3, PC4, PC5, PD2, PD3, PD4, PD5, PD6, PD7,
+    adc::{
+        channel::{ADC6, ADC7},
+        AdcChannel,
     },
+    hal::{
+        port::{
+            PB0, PB1, PB2, PB3, PB4, PC0, PC1, PC2, PC3, PC4, PC5, PD2, PD3, PD4, PD5, PD6, PD7,
+        },
+        Atmega,
+    },
+    pac::ADC,
     port::{mode::Output, Pin},
     prelude::*,
     Adc,
@@ -118,6 +125,20 @@ impl SegmentPins {
     }
 }
 
+struct IOSelect<'p> {
+    display_no: usize,
+    pin: &'p mut Pin<Output>,
+}
+
+impl IOSelect<'_> {
+    fn set_on(&mut self) {
+        self.pin.set_high()
+    }
+    fn set_off(&mut self) {
+        self.pin.set_low()
+    }
+}
+
 struct IOPins([Pin<Output>; 9]);
 
 impl IOPins {
@@ -145,23 +166,11 @@ impl IOPins {
         ])
     }
 
-    fn scan_output(&mut self, mut segment: impl FnMut(usize) -> ()) {
-        for (no, d) in self.0.iter_mut().enumerate() {
-            segment(no);
-            d.set_high();
-            arduino_hal::delay_ms(1);
-            d.set_low();
-        }
-    }
-
-    fn scan_input(&mut self, mut segment: impl FnMut(usize) -> ()) {
-        for (no, d) in self.0.iter_mut().enumerate() {
-            d.set_high();
-            arduino_hal::delay_ms(1);
-            segment(no);
-            arduino_hal::delay_ms(1);
-            d.set_low();
-        }
+    fn iter_mut(&mut self) -> impl Iterator<Item = IOSelect> {
+        self.0
+            .iter_mut()
+            .enumerate()
+            .map(|(display_no, pin)| IOSelect { display_no, pin })
     }
 }
 
@@ -276,35 +285,24 @@ impl Default for DispalyState {
     }
 }
 
-impl DispalyState {
-    fn scan(&self, dp: &mut IOPins, seg: &mut SegmentPins) {
-        dp.scan_output(|no| {
-            self.0[no].apply(seg);
-        });
-        seg.set_off();
-    }
-}
-
 struct Input<KN, KO> {
     kn: KN,
     ko: KO,
 }
 
-impl<KN, KO> Input<KN, KO> {
+impl<KN: AdcChannel<Atmega, ADC>, KO: AdcChannel<Atmega, ADC>> Input<KN, KO> {
     fn new(kn: KN, ko: KO) -> Input<KN, KO> {
         Input { kn, ko }
     }
 
-    fn scan(&self, io: &mut IOPins, adc: &mut Adc) -> Option<(usize, u16, u16)> {
-        let mut out = None;
-        io.scan_input(|no| {
-            let kn = adc.read_blocking(&ADC7);
-            let ko = adc.read_blocking(&ADC6);
-            if kn > 500 || ko > 500 {
-                out = Some((no, kn, ko));
-            }
-        });
-        out
+    fn read(&self, adc: &mut Adc) -> Option<(u16, u16)> {
+        let kn = adc.read_blocking(&self.kn);
+        let ko = adc.read_blocking(&self.ko);
+        if kn > 500 || ko > 500 {
+            Some((kn, ko))
+        } else {
+            None
+        }
     }
 }
 
@@ -359,9 +357,22 @@ fn main() -> ! {
     display.0[8] = SegmentState::Num(8, false);
 
     loop {
-        display.scan(&mut io, &mut seg);
-        arduino_hal::delay_ms(10);
-        if let Some((no, kn, ko)) = input.scan(&mut io, &mut adc) {
+        let mut key: Option<(usize, u16, u16)> = None;
+        for (mut io_select, ss) in io.iter_mut().zip(display.0.iter()) {
+            ss.apply(&mut seg);
+            io_select.set_on();
+            arduino_hal::delay_ms(1);
+            io_select.set_off();
+            seg.set_off();
+            io_select.set_on();
+            arduino_hal::delay_ms(1);
+            if let Some((kn, ko)) = input.read(&mut adc) {
+                key = Some((io_select.display_no, kn, ko))
+            }
+            io_select.set_off();
+        }
+
+        if let Some((no, kn, ko)) = key {
             ufmt::uwriteln!(&mut serial, "no: {} kn: {} ko: {}", no, kn, ko).unwrap_infallible();
         }
     }