Quadrature Encoder Interface API

Author: Marwan SMOUNI

src/lib.rs

@@ -156,6 +156,9 @@ pub mod qspi;
 #[cfg(any(feature = "stm32f765", feature = "stm32f767", feature = "stm32f769"))]
 pub mod adc;
 
+#[cfg(any(feature = "stm32f765", feature = "stm32f767", feature = "stm32f769"))]
+pub mod qei;
+
 #[cfg(feature = "ltdc")]
 pub mod ltdc;
 

src/qei.rs

@@ -0,0 +1,173 @@
+//! Quadrature Encoder Interface API
+
+use crate::rcc::APB1;
+use stm32f7::stm32f7x7::{TIM2, TIM3, TIM4, TIM5};
+
+#[derive(Debug)]
+pub enum Direction {
+    Upcounting,
+    Downcounting,
+}
+
+/// SMS[3:0] (Slave Mode Selection) register
+#[derive(Debug, Clone, Copy)]
+pub enum SlaveMode {
+    /// Slave mode disabled - if CEN = ‘1’ then the prescaler is clocked directly by the internal
+    /// clock.
+    Disable = 0b0000,
+
+    /// Counter counts up/down on TI2FP1 edge depending on TI1FP2 level.
+    EncoderMode1 = 0b0001,
+
+    /// Encoder mode 2 - Counter counts up/down on TI1FP2 edge depending on TI2FP1 level.
+    EncoderMode2 = 0b0010,
+
+    /// Encoder mode 3 - Counter counts up/down on both TI1FP1 and TI2FP2 edges depending on the
+    /// level of the other input.
+    EncoderMode3 = 0b0011,
+
+    /// Reset Mode - Rising edge of the selected trigger input (TRGI) reinitializes the counter and
+    /// generates an update of the registers.
+    ResetMode = 0b0100,
+
+    /// Gated Mode - The counter clock is enabled when the trigger input (TRGI) is high. The
+    /// counter stops (but is not reset) as soon as the trigger becomes low. Both start and stop of
+    /// the counter are controlled.
+    GatedMode = 0b0101,
+
+    /// Trigger Mode - The counter starts at a rising edge of the trigger TRGI (but it is not
+    /// reset). Only the start of the counter is controlled.
+    TriggerMode = 0b0110,
+
+    /// External Clock Mode 1 - Rising edges of the selected trigger (TRGI) clock the counter.
+    ExternalClockMode1 = 0b0111,
+
+    /// Combined reset + trigger mode - Rising edge of the selected trigger input (TRGI)
+    /// reinitializes the counter, generates an update of the registers and starts the counter.
+    Combined = 0b1000,
+}
+
+/// Quadrature Encoder Interface (QEI) options
+#[derive(Debug, Clone, Copy)]
+pub struct QeiOptions {
+    /// Encoder slave mode
+    pub slave_mode: SlaveMode,
+
+    /// Autoreload value
+    ///
+    /// This value allows the maximum count to be configured. Setting a lower value
+    /// will overflow the counter to 0 sooner.
+    pub auto_reload_value: u32,
+}
+
+impl Default for QeiOptions {
+    fn default() -> Self {
+        Self {
+            slave_mode: SlaveMode::EncoderMode3,
+            auto_reload_value: core::u32::MAX,
+        }
+    }
+}
+
+///
+/// Make sure that pin_ch1 and pin_ch2 are used in the corresponding alternative mode.
+/// ----------------------------------
+///   TIMx |  PIN_CH1   |  PIN_CH2   |
+/// -------|------------|------------|
+///   TIM2 | PA0\<AF1>  | PB3\<AF1>  |
+///   TIM2 | PA0\<AF1>  | PA1\<AF1>  |
+///   TIM2 | PA5\<AF1>  | PB3\<AF1>  |
+///   TIM2 | PA5\<AF1>  | PA1\<AF1>  |
+///   TIM2 | PA15\<AF1> | PB3\<AF1>  |
+///   TIM2 | PA15\<AF1> | PA1\<AF1>  |
+///   TIM3 | PA6\<AF2>  | PA7\<AF2>  |
+///   TIM3 | PA6\<AF2>  | PB5\<AF2>  |
+///   TIM3 | PA6\<AF2>  | PC7\<AF2>  |
+///   TIM3 | PB4\<AF2>  | PA7\<AF2>  |
+///   TIM3 | PB4\<AF2>  | PB5\<AF2>  |
+///   TIM3 | PB4\<AF2>  | PC7\<AF2>  |
+///   TIM3 | PC6\<AF2>  | PA7\<AF2>  |
+///   TIM3 | PC6\<AF2>  | PB5\<AF2>  |
+///   TIM3 | PC6\<AF2>  | PC7\<AF2>  |
+///   TIM4 | PB6\<AF2>  | PB7\<AF2>  |
+///   TIM4 | PB6\<AF2>  | PD13\<AF2> |
+///   TIM4 | PD12\<AF2> | PB7\<AF2>  |
+///   TIM4 | PD12\<AF2> | PD13\<AF2> |
+///   TIM4 | PD12\<AF2> | PD13\<AF2> |
+///   TIM5 | PA0\<AF2>  | PA1\<AF2>  |
+pub struct Qei<PIN1, PIN2, TIM> {
+    tim: TIM,
+    _pin_ch1: PIN1,
+    _pin_ch2: PIN2,
+}
+
+// General-purpose timers (TIM2/TIM3/TIM4/TIM5) : Up, Down, Up/Down
+macro_rules! hal_qei {
+    ($fct:ident,$TIMX:ty, $bits:ty, $timen:ident, $timrst:ident) => {
+        //, $CH1:ident<$AFCH1:ty>, $CH2:ident<$AFCH2:ty>) => {
+        impl<PIN1, PIN2> Qei<PIN1, PIN2, $TIMX> {
+            //Qei<$CH1<Alternate<$AFCH1>>, $CH2<Alternate<$AFCH2>>, $TIM> {
+            pub fn $fct(
+                tim: $TIMX,
+                pin_ch1: PIN1, //$CH1<Alternate<$AFCH1>>,
+                pin_ch2: PIN2, //$CH2<Alternate<$AFCH2>>,
+                apb1: &mut APB1,
+                options: QeiOptions,
+            ) -> Self {
+                // enable and reset peripheral to a clean slate state
+                apb1.enr().modify(|_, w| w.$timen().set_bit());
+                apb1.rstr().modify(|_, w| w.$timrst().set_bit());
+                apb1.rstr().modify(|_, w| w.$timrst().clear_bit());
+
+                // Configure TxC1 and TxC2 as captures
+                tim.ccmr1_output()
+                    .write(|w| unsafe { w.cc1s().bits(0b01).cc2s().bits(0b01) });
+
+                // enable and configure to capture on rising edge
+                tim.ccer.write(|w| {
+                    w.cc1e()
+                        .set_bit()
+                        .cc1p()
+                        .clear_bit()
+                        .cc2e()
+                        .set_bit()
+                        .cc2p()
+                        .clear_bit()
+                });
+
+                // configure as quadrature encoder
+                tim.smcr.write(|w| w.sms().bits(options.slave_mode as u8));
+                tim.arr
+                    .write(|w| unsafe { w.bits(options.auto_reload_value) });
+                tim.cr1.write(|w| w.cen().set_bit());
+
+                Self {
+                    tim,
+                    _pin_ch1: pin_ch1,
+                    _pin_ch2: pin_ch2,
+                }
+            }
+
+            pub fn read_count(&self) -> $bits {
+                self.tim.cnt.read().bits() as $bits
+            }
+
+            pub fn read_direction(&self) -> Direction {
+                if self.tim.cr1.read().dir().bit_is_clear() {
+                    Direction::Upcounting
+                } else {
+                    Direction::Downcounting
+                }
+            }
+
+            pub fn release(self) -> ($TIMX, PIN1, PIN2) {
+                (self.tim, self._pin_ch1, self._pin_ch2)
+            }
+        }
+    };
+}
+
+hal_qei! {qei_tim2, TIM2, u32, tim2en, tim2rst}
+hal_qei! {qei_tim3, TIM3, u16, tim3en, tim3rst}
+hal_qei! {qei_tim4, TIM4, u16, tim4en, tim4rst}
+hal_qei! {qei_tim5, TIM5, u32, tim5en, tim5rst}