3 files changed, 58 insertions, 47 deletions

diff --git a/embassy-stm32/build.rs b/embassy-stm32/build.rs
index 8cddb68f9..fa493da84 100644
--- a/embassy-stm32/build.rs
+++ b/embassy-stm32/build.rs
@@ -1352,28 +1352,28 @@ fn main() {
         (("tsc", "G8_IO2"), quote!(crate::tsc::G8IO2Pin)),
         (("tsc", "G8_IO3"), quote!(crate::tsc::G8IO3Pin)),
         (("tsc", "G8_IO4"), quote!(crate::tsc::G8IO4Pin)),
-        (("lcd", "SEG"), quote!(crate::lcd::SegComPin)),
-        (("lcd", "COM"), quote!(crate::lcd::SegComPin)),
+        (("lcd", "SEG"), quote!(crate::lcd::SegPin)),
+        (("lcd", "COM"), quote!(crate::lcd::ComPin)),
+        (("lcd", "VLCD"), quote!(crate::lcd::VlcdPin)),
         (("dac", "OUT1"), quote!(crate::dac::DacPin<Ch1>)),
         (("dac", "OUT2"), quote!(crate::dac::DacPin<Ch2>)),
     ].into();
 
-    let mut seen_lcd_pins = HashSet::new();
-
     for p in METADATA.peripherals {
         if let Some(regs) = &p.registers {
             let mut adc_pairs: BTreeMap<u8, (Option<Ident>, Option<Ident>)> = BTreeMap::new();
+            let mut seen_lcd_seg_pins = HashSet::new();
 
             for pin in p.pins {
                 let mut key = (regs.kind, pin.signal);
 
-                // LCD is special
+                // LCD is special. There are so many pins!
                 if regs.kind == "lcd" {
                     key.1 = pin.signal.trim_end_matches(char::is_numeric);
 
-                    // Some lcd pins have multiple lcd functions
-                    // Dedup so they don't get the trait implemented twice
-                    if !seen_lcd_pins.insert(pin.pin) {
+                    if key.1 == "SEG" && !seen_lcd_seg_pins.insert(pin.pin) {
+                        // LCD has SEG pins multiplexed in the peripheral
+                        // This means we can see them twice. We need to skip those so we're not impl'ing the trait twice
                         continue;
                     }
                 }
diff --git a/embassy-stm32/src/lcd.rs b/embassy-stm32/src/lcd.rs
index 3a890e529..66a9386b7 100644
--- a/embassy-stm32/src/lcd.rs
+++ b/embassy-stm32/src/lcd.rs
@@ -168,6 +168,12 @@ impl<'d, T: Instance> Lcd<'d, T> {
             AfType::output(crate::gpio::OutputType::PushPull, crate::gpio::Speed::VeryHigh),
         );
 
+        assert_eq!(
+            pins.iter().filter(|pin| !pin.is_seg).count(),
+            config.duty.num_com_pins() as usize,
+            "The number of provided COM pins is not the same as the duty configures"
+        );
+
         // Set the pins
         for pin in pins {
             pin.pin.set_as_af(
@@ -375,23 +381,31 @@ impl<'d, T: Instance> Drop for Lcd<'d, T> {
 pub struct LcdPin<'d, T: Instance> {
     pin: Peri<'d, AnyPin>,
     af_num: u8,
+    is_seg: bool,
     _phantom: PhantomData<T>,
 }
 
-impl<'d, T: Instance, Pin: SegComPin<T>> From<Peri<'d, Pin>> for LcdPin<'d, T> {
-    fn from(value: Peri<'d, Pin>) -> Self {
-        Self::new(value)
+impl<'d, T: Instance> LcdPin<'d, T> {
+    /// Construct an LCD pin from any pin that supports it
+    pub fn new_seg(pin: Peri<'d, impl SegPin<T>>) -> Self {
+        let af = pin.af_num();
+
+        Self {
+            pin: pin.into(),
+            af_num: af,
+            is_seg: true,
+            _phantom: PhantomData,
+        }
     }
-}
 
-impl<'d, T: Instance> LcdPin<'d, T> {
     /// Construct an LCD pin from any pin that supports it
-    pub fn new(pin: Peri<'d, impl SegComPin<T>>) -> Self {
+    pub fn new_com(pin: Peri<'d, impl ComPin<T>>) -> Self {
         let af = pin.af_num();
 
         Self {
             pin: pin.into(),
             af_num: af,
+            is_seg: false,
             _phantom: PhantomData,
         }
     }
@@ -405,13 +419,10 @@ trait SealedInstance: crate::rcc::SealedRccPeripheral + PeripheralType {
 #[allow(private_bounds)]
 pub trait Instance: SealedInstance + RccPeripheral + 'static {}
 
-pin_trait!(SegComPin, Instance);
+pin_trait!(SegPin, Instance);
+pin_trait!(ComPin, Instance);
 pin_trait!(VlcdPin, Instance);
 
-// TODO: pull into build.rs, but the metapack doesn't have this info
-pin_trait_impl!(crate::lcd::VlcdPin, LCD, PC3, 11);
-pin_trait_impl!(crate::lcd::VlcdPin, LCD, PB2, 11);
-
 foreach_peripheral!(
     (lcd, $inst:ident) => {
         impl crate::lcd::SealedInstance for peripherals::$inst {
diff --git a/examples/stm32u0/src/bin/lcd.rs b/examples/stm32u0/src/bin/lcd.rs
index f401b1dcd..39db5c9c8 100644
--- a/examples/stm32u0/src/bin/lcd.rs
+++ b/examples/stm32u0/src/bin/lcd.rs
@@ -43,34 +43,34 @@ async fn main(_spawner: Spawner) {
         config,
         p.PC3,
         [
-            LcdPin::from(p.PA8),
-            LcdPin::from(p.PA9),
-            LcdPin::from(p.PA10),
-            LcdPin::from(p.PB1),
-            LcdPin::from(p.PB9),
-            LcdPin::from(p.PB11),
-            LcdPin::from(p.PB14),
-            LcdPin::from(p.PB15),
-            LcdPin::from(p.PC4),
-            LcdPin::from(p.PC5),
-            LcdPin::from(p.PC6),
-            LcdPin::from(p.PC8),
-            LcdPin::from(p.PC9),
-            LcdPin::from(p.PC10),
-            LcdPin::from(p.PC11),
-            LcdPin::from(p.PD8),
-            LcdPin::from(p.PD9),
-            LcdPin::from(p.PD12),
-            LcdPin::from(p.PD13),
-            LcdPin::from(p.PD0),
-            LcdPin::from(p.PD1),
-            LcdPin::from(p.PD3),
-            LcdPin::from(p.PD4),
-            LcdPin::from(p.PD5),
-            LcdPin::from(p.PD6),
-            LcdPin::from(p.PE7),
-            LcdPin::from(p.PE8),
-            LcdPin::from(p.PE9),
+            LcdPin::new_com(p.PA8),
+            LcdPin::new_com(p.PA9),
+            LcdPin::new_com(p.PA10),
+            LcdPin::new_seg(p.PB1),
+            LcdPin::new_com(p.PB9),
+            LcdPin::new_seg(p.PB11),
+            LcdPin::new_seg(p.PB14),
+            LcdPin::new_seg(p.PB15),
+            LcdPin::new_seg(p.PC4),
+            LcdPin::new_seg(p.PC5),
+            LcdPin::new_seg(p.PC6),
+            LcdPin::new_seg(p.PC8),
+            LcdPin::new_seg(p.PC9),
+            LcdPin::new_seg(p.PC10),
+            LcdPin::new_seg(p.PC11),
+            LcdPin::new_seg(p.PD8),
+            LcdPin::new_seg(p.PD9),
+            LcdPin::new_seg(p.PD12),
+            LcdPin::new_seg(p.PD13),
+            LcdPin::new_seg(p.PD0),
+            LcdPin::new_seg(p.PD1),
+            LcdPin::new_seg(p.PD3),
+            LcdPin::new_seg(p.PD4),
+            LcdPin::new_seg(p.PD5),
+            LcdPin::new_seg(p.PD6),
+            LcdPin::new_seg(p.PE7),
+            LcdPin::new_seg(p.PE8),
+            LcdPin::new_seg(p.PE9),
         ],
     );