Start reading registers

src/mouse_sensor.rs

@@ -1,3 +1,5 @@
+use core::mem;
+
 use cortex_m::prelude::_embedded_hal_spi_FullDuplex;
 use embedded_hal::digital::v2::OutputPin;
 use fugit::HertzU32;
@@ -27,6 +29,26 @@ impl MouseSensor {
     const READ: u8 = 0x7F;
     const WRITE: u8 = 0x80;
 
+    const REG_PRODUCT_ID1: u8 = 0x00;
+    const REG_PRODUCT_ID2: u8 = 0x01;
+    const REG_MOTION_STATUS: u8 = 0x02;
+    const REG_DELTA_X: u8 = 0x03;
+    const REG_DELTA_Y: u8 = 0x04;
+    const REG_OPERATION_MODE: u8 = 0x05;
+    const REG_CONFIGURATION: u8 = 0x06;
+    const REG_WRITE_PROTECT: u8 = 0x09;
+    const REG_SLEEP1: u8 = 0x0A;
+    const REG_SLEEP2: u8 = 0x0B;
+    const REG_SLEEP3: u8 = 0x0C;
+    const REG_CPI_X: u8 = 0x0D;
+    const REG_CPI_Y: u8 = 0x0E;
+    const REG_DELTA_XY_HI: u8 = 0x12;
+    const REG_IQC: u8 = 0x13;
+    const REG_SHUTTER: u8 = 0x14;
+    const REG_FRAME_AVG: u8 = 0x17;
+    const REG_MOUSE_OPTION: u8 = 0x19;
+    const REG_SPI_MODE: u8 = 0x26;
+
     pub fn new(
         pins: Pins,
         resets: &mut RESETS,
@@ -90,6 +112,37 @@ impl MouseSensor {
     }
 
     pub fn read_movement(&mut self) -> Option<(i8, i8)> {
-        todo!()
+        let (motion, x_overflow, y_overflow) = self.motion_detected();
+
+        if motion {
+            if x_overflow || y_overflow {
+                return None;
+            }
+
+            let x = self.delta_x();
+            let y = self.delta_y();
+
+            Some((x, y))
+        } else {
+            None
+        }
+    }
+
+    pub fn delta_x(&mut self) -> i8 {
+        unsafe { mem::transmute(self.read(Self::REG_DELTA_X)) }
+    }
+
+    pub fn delta_y(&mut self) -> i8 {
+        unsafe { mem::transmute(self.read(Self::REG_DELTA_Y)) }
+    }
+
+    pub fn motion_detected(&mut self) -> (bool, bool, bool) {
+        let reg = self.read(Self::REG_MOTION_STATUS);
+
+        let motion = (reg & 0b10000000) != 0;
+        let x_overflow = (reg & 0b00010000) != 0;
+        let y_overflow = (reg & 0b00001000) != 0;
+
+        (motion, x_overflow, y_overflow)
     }
 }