Get I²C basics working.

2 files changed, 65 insertions, 2 deletions

diff --git a/ble/src/i2c.rs b/ble/src/i2c.rs
new file mode 100644
index 0000000..13f5a5a
--- /dev/null
+++ b/ble/src/i2c.rs
@@ -0,0 +1,43 @@
+use log::{error, info, trace};
+use nrf52840_hal::twis::{self, Twis, TwisInterrupt};
+
+pub fn setup<T>(mut twis: Twis<T>) -> impl FnMut()
+where
+    T: twis::Instance,
+{
+    // TODO: we only care about `Write` and `Stopped`.
+    twis.enable_interrupt(TwisInterrupt::Stopped);
+    twis.enable_interrupt(TwisInterrupt::Error);
+    twis.enable_interrupt(TwisInterrupt::RxStarted);
+    twis.enable_interrupt(TwisInterrupt::TxStarted);
+    twis.enable_interrupt(TwisInterrupt::Write);
+    twis.enable_interrupt(TwisInterrupt::Read);
+
+    let mut buf: [u8; 255] = [0; 255];
+    move || handler(&mut twis, &mut buf)
+}
+
+fn handler<T>(twis: &mut Twis<T>, buf: &mut [u8])
+where
+    T: twis::Instance,
+{
+    if twis.get_event_triggered(TwisInterrupt::Stopped, true) {
+        trace!("i²c stopped: {}", twis.amount());
+    } else if twis.get_event_triggered(TwisInterrupt::Error, true) {
+        trace!("i²c error");
+    } else if twis.get_event_triggered(TwisInterrupt::RxStarted, true) {
+        trace!("i²c rxstarted");
+    } else if twis.get_event_triggered(TwisInterrupt::TxStarted, true) {
+        trace!("i²c txstarted");
+    } else if twis.get_event_triggered(TwisInterrupt::Write, true) {
+        trace!("i²c write");
+        match twis.read(buf) {
+            Ok(len) => info!("buf {}: {:?}", len, &buf[..len]),
+            Err(e) => error!("{:?}", e),
+        }
+    } else if twis.get_event_triggered(TwisInterrupt::Read, true) {
+        trace!("i²c read");
+    } else {
+        trace!("i²c unknown");
+    }
+}
diff --git a/ble/src/main.rs b/ble/src/main.rs
index 4430e98..2da6de9 100644
--- a/ble/src/main.rs
+++ b/ble/src/main.rs
@@ -3,6 +3,7 @@
 #![no_std]
 #![no_main]
 
+mod i2c;
 mod logger;
 mod macros;
 mod rtc;
@@ -21,12 +22,15 @@ use nrf52840_mdk_bsp::{
     hal::{
         gpio::{Floating, Input, Level, Output, Pin, PushPull},
         target::{interrupt, Interrupt, UARTE0},
+        twis::{self, Twis},
         uarte::{self, Baudrate as UartBaudrate, Parity as UartParity, Uarte},
         Clocks, Rtc,
     },
     Board,
 };
 
+const I2C_ADDR: u8 = 4;
+
 // TODO:
 //   * set up serial reader for trinket
 //   * set up i²c interface for keyboard reports
@@ -49,6 +53,14 @@ fn main() -> ! {
 
     let mut nvic = nrf52.NVIC;
     let mut rtc_handler = rtc::setup(Rtc::new(nrf52.RTC0), Clocks::new(nrf52.CLOCK));
+    let mut twis_handler = i2c::setup(Twis::new(
+        I2C_ADDR,
+        nrf52.TWIS0,
+        twis::Pins {
+            scl: nrf52.pins.P0_06.into_floating_input().degrade(),
+            sda: nrf52.pins.P0_07.into_floating_input().degrade(),
+        },
+    ));
 
     let txp = nrf52
         .pins
@@ -61,6 +73,8 @@ fn main() -> ! {
     HANDLERS.with_overrides(|hs| {
         hs.register(0, &mut rtc_handler);
         nvic.enable(Interrupt::RTC0);
+        hs.register(1, &mut twis_handler);
+        nvic.enable(Interrupt::SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0);
 
         info!("Bootstrap complete.");
 
@@ -74,6 +88,7 @@ fn main() -> ! {
                 trace!(".");
                 write!(uarte1, "!").expect("uarte1 write");
             }
+
             wfi();
         }
     });
@@ -87,8 +102,8 @@ where
     Uarte::new(
         uarte,
         uarte::Pins {
-            txd: tx.into_push_pull_output(Level::High),
-            rxd: rx.into_floating_input(),
+            txd: tx,
+            rxd: rx,
             cts: None,
             rts: None,
         },
@@ -112,3 +127,8 @@ fn HardFault(ef: &ExceptionFrame) -> ! {
 fn RTC0() {
     HANDLERS.call(0);
 }
+
+#[interrupt]
+fn SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0() {
+    HANDLERS.call(1);
+}