2 files changed, 265 insertions, 1 deletions
diff --git a/src/cirque.rs b/src/cirque.rs
new file mode 100644
index 0000000..b1f5fae
--- /dev/null
+++ b/src/cirque.rs
@@ -0,0 +1,255 @@
+/// Support for the Cirque Pinnacle 1CA027.
+use core::cmp::{max, min};
+use embedded_hal::{
+    digital::v2::{InputPin, OutputPin},
+    spi,
+};
+use nb;
+use stm32f1xx_hal::rcc::Clocks;
+
+/// Default I²C address.
+const I2C_ADDR: u8 = 0x2a;
+
+// the maximum reportable units
+const MAX_X: u16 = 2047;
+const MAX_Y: u16 = 1535;
+
+// the lowest reachable units
+const CLAMP_X_MIN: u16 = 127;
+const CLAMP_Y_MIN: u16 = 63;
+
+// the highest reachable units
+const CLAMP_X_MAX: u16 = 1919;
+const CLAMP_Y_MAX: u16 = 1471;
+
+// masks for register access protocol
+const WRITE_MASK: u8 = 0x80;
+const READ_MASK: u8 = 0xa0;
+
+fn clamp<T: Ord>(val: T, low: T, high: T) -> T {
+    min(max(low, val), high)
+}
+
+/// Register Access Protocol addresses.
+#[repr(u8)]
+enum RAPAddress {
+    FirmwareID = 0x00,
+    FirmwareVersion = 0x01,
+    Status1 = 0x02,
+    SysConfig1 = 0x03,
+    FeedConfig1 = 0x04,
+    FeedConfig2 = 0x05,
+    FeedConfig3 = 0x06,
+    CalConfig1 = 0x07,
+    PS2AuxControl = 0x08,
+    SampleRate = 0x09,
+    ZIdle = 0x0a,
+    ZScaler = 0x0b,
+    SleepInterval = 0x0c,
+    SleepDelay = 0x0d,
+    Reserved0 = 0x0e,
+    Reserved1 = 0x0f,
+    Reserved2 = 0x10,
+    Reserved3 = 0x11,
+    PacketByte0 = 0x12,
+    PacketByte1 = 0x13,
+    PacketByte2 = 0x14,
+    PacketByte3 = 0x15,
+    PacketByte4 = 0x16,
+    PacketByte5 = 0x17,
+    Reserved4 = 0x18,
+    Reserved5 = 0x19,
+    Reserved6 = 0x1a,
+    ERAValue = 0x1b,
+    ERAHighByte = 0x1c,
+    ERALowByte = 0x1d,
+    ERAControl = 0x1e,
+    ProductID = 0x1f,
+}
+
+trait SPIWriter<Word>: spi::FullDuplex<Word> {
+    fn write(&mut self, buf: &[Word]) -> Result<(), Self::Error>;
+    fn transfer(&mut self, buf: &mut [Word]) -> Result<(), Self::Error>;
+}
+
+impl<T, Word> SPIWriter<Word> for T
+where
+    T: spi::FullDuplex<Word>,
+    Word: Copy,
+{
+    fn write(&mut self, buf: &[Word]) -> Result<(), Self::Error> {
+        for i in buf {
+            // TODO: figure out why the ? operator doesn't work here.
+            self.send(*i);
+        }
+        Ok(())
+    }
+
+    fn transfer(&mut self, buf: &mut [Word]) -> Result<(), Self::Error> {
+        for i in buf.iter_mut() {
+            // TODO: figure out why the ? operator doesn't work here.
+            self.send(*i);
+            if let Ok(v) = self.read() {
+                *i = v;
+            }
+        }
+        Ok(())
+    }
+}
+
+#[allow(unused)]
+#[derive(Debug)]
+pub struct TouchData {
+    x: u16,
+    y: u16,
+    z: u8,
+    buttons: u8,
+    is_pressed: bool,
+}
+
+impl TouchData {
+    pub fn clamp(&mut self) {
+        self.x = clamp(self.x, CLAMP_X_MIN, CLAMP_X_MAX);
+        self.y = clamp(self.y, CLAMP_Y_MIN, CLAMP_Y_MAX);
+    }
+
+    pub fn scale_to(&mut self, width: u16, height: u16) {
+        let width_factor = width / (CLAMP_X_MAX - CLAMP_X_MIN);
+        let height_factor = height / (CLAMP_Y_MAX - CLAMP_Y_MIN);
+
+        self.clamp();
+        self.x -= CLAMP_X_MIN;
+        self.y -= CLAMP_Y_MIN;
+
+        self.x *= width_factor;
+        self.y *= height_factor;
+    }
+}
+
+pub struct Cirque<C, D>
+where
+    C: OutputPin,
+    D: InputPin,
+{
+    cs_pin: C,
+    dr_pin: D,
+    sysclk_speed: u32,
+}
+
+impl<C, D> Cirque<C, D>
+where
+    C: OutputPin,
+    D: InputPin,
+{
+    pub fn new<S>(
+        cs_pin: C,
+        dr_pin: D,
+        spi: &mut S,
+        clocks: Clocks,
+    ) -> nb::Result<Self, S::Error>
+    where
+        S: embedded_hal::spi::FullDuplex<u8>,
+    {
+        let sysclk_speed = clocks.sysclk().raw();
+        let mut res = Self {
+            cs_pin,
+            dr_pin,
+            sysclk_speed,
+        };
+        res.init(spi)?;
+        Ok(res)
+    }
+
+    fn init<S>(&mut self, spi: &mut S) -> nb::Result<(), S::Error>
+    where
+        S: embedded_hal::spi::FullDuplex<u8>,
+    {
+        self.cs_pin.set_high().ok();
+        self.clear_flags(spi)?;
+
+        // SysConfig
+        self.wr(spi, 0x03, 0x00)?;
+        // FeedConfig2
+        self.wr(spi, 0x05, 0x1f)?;
+        // FeedConfig1
+        self.wr(spi, 0x04, 0x03)?;
+        // ZIdleCount
+        self.wr(spi, 0x0a, 0x05)?;
+
+        Ok(())
+    }
+
+    fn clear_flags<S>(&mut self, spi: &mut S) -> nb::Result<(), S::Error>
+    where
+        S: embedded_hal::spi::FullDuplex<u8>,
+    {
+        self.wr(spi, 0x02, 0x00)?;
+
+        cortex_m::asm::delay(50 * self.sysclk_speed / 1_000_000);
+
+        Ok(())
+    }
+
+    pub fn poll<S>(&mut self, spi: &mut S) -> nb::Result<TouchData, S::Error>
+    where
+        S: embedded_hal::spi::FullDuplex<u8>,
+    {
+        if self.dr_pin.is_high().unwrap_or(false) {
+            self.read_coords(spi)
+        } else {
+            Err(nb::Error::WouldBlock)
+        }
+    }
+
+    fn read_coords<S>(&mut self, spi: &mut S) -> nb::Result<TouchData, S::Error>
+    where
+        S: embedded_hal::spi::FullDuplex<u8>,
+    {
+        let mut buf: [u8; 6] = [0xfc; 6];
+        self.rd(spi, 0x12, &mut buf)?;
+        self.clear_flags(spi)?;
+
+        let x = buf[2] as u16 | ((buf[4] as u16 & 0x0f) << 8);
+        let y = buf[3] as u16 | ((buf[4] as u16 & 0xf0) << 4);
+        let z = buf[5] & 0x3f;
+        let buttons = buf[0] & 0x3f;
+        let is_pressed = x != 0;
+
+        assert!(x < MAX_X);
+        assert!(y < MAX_Y);
+
+        Ok(TouchData {
+            x,
+            y,
+            z,
+            buttons,
+            is_pressed,
+        })
+    }
+
+    fn rd<S>(&mut self, spi: &mut S, cmd: u8, buf: &mut [u8]) -> Result<(), S::Error>
+    where
+        S: embedded_hal::spi::FullDuplex<u8>,
+    {
+        let cmd = cmd | READ_MASK;
+        self.cs_pin.set_low().ok();
+        let res = spi
+            .write(&[cmd, 0xfc, 0xfc])
+            .and_then(|_| spi.transfer(buf));
+        self.cs_pin.set_high().ok();
+
+        Ok(())
+    }
+
+    fn wr<S>(&mut self, spi: &mut S, addr: u8, data: u8) -> Result<(), S::Error>
+    where
+        S: embedded_hal::spi::FullDuplex<u8>,
+    {
+        let cmd = addr | WRITE_MASK;
+        self.cs_pin.set_low().ok();
+        let res = spi.write(&[cmd, data]);
+        self.cs_pin.set_high().ok();
+
+        res
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index d0dfe1a..ce5f346 100755
--- a/src/main.rs
+++ b/src/main.rs
@@ -3,9 +3,11 @@
 
 //extern crate panic_semihosting;
 
+mod cirque;
 mod led;
 mod log;
 
+use cirque::Cirque;
 use led::LED;
 
 use cortex_m::{
@@ -82,7 +84,7 @@ fn main() -> ! {
         phase: Phase::CaptureOnSecondTransition,
         polarity: Polarity::IdleHigh,
     };
-    let spi = Spi::spi1(
+    let mut spi = Spi::spi1(
         dp.SPI1,
         (sck_pin, miso_pin, mosi_pin),
         &mut afio.mapr,
@@ -90,6 +92,7 @@ fn main() -> ! {
         1.MHz(),
         clocks,
     );
+    let mut cirque = Cirque::new(cs_pin, dr_pin, &mut spi, clocks).expect("couldn't init touch pad");
 
     // BluePill board has a pull-up resistor on the D+ line.
     // Pull the D+ pin down to send a RESET condition to the USB bus.
@@ -119,6 +122,12 @@ fn main() -> ! {
 
     loop {
         logln!(".");
+
+        if let Ok(mut td) = cirque.poll(&mut spi) {
+            td.scale_to(1920, 1080);
+            logln!("td: {:?}", td);
+        }
+
         if !usb_dev.poll(&mut [&mut serial]) {
             continue;
         }