Fix stall when trying to i2c blocking read when INT is not high

mengfanzhong · Apr 8, 2020 · 29909b5 · 29909b5
1 parent 6133d10
commit 29909b5
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Showing 2 changed files with 18 additions and 21 deletions.
diff --git a/examples/touchpad.rs b/examples/touchpad.rs
@@ -80,15 +80,6 @@ fn main() -> ! {
     // random number generator peripheral
     let mut rng = dp.RNG.constrain();
 
-    // // pushbutton input GPIO: P0.13
-    // let mut _user_butt = port0.p0_13.into_floating_input().degrade();
-    // // must drive this pin high to enable pushbutton
-    // let mut _user_butt_en =
-    //     port0.p0_15.into_push_pull_output(Level::High).degrade();
-    // vibration motor output: drive low to activate motor
-    // let mut vibe = port0.p0_16.into_push_pull_output(Level::Low).degrade();
-    // delay_source.delay_ms(100u8);
-    // let _ = vibe.set_high();
 
     // internal i2c0 bus devices: BMA421 (accel), HRS3300 (hrs), CST816S (TouchPad)
     // BMA421-INT:  P0.08
@@ -140,7 +131,7 @@ fn main() -> ! {
     draw_background(&mut display, &mut display_csn);
 
     // setup touchpad external interrupt pin: P0.28/AIN4 (TP_INT)
-    let touch_int  = port0.p0_28.into_floating_input().degrade();
+    let touch_int  = port0.p0_28.into_pullup_input().degrade();
     // setup touchpad reset pin: P0.10/NFC2 (TP_RESET)
     let touch_rst  = port0.p0_10.into_push_pull_output(Level::High).degrade();
 

diff --git a/src/lib.rs b/src/lib.rs
@@ -124,17 +124,23 @@ where
     /// Reads events into the event buffer provided
     pub fn read_one_touch_event(&mut self, ) -> Option<TouchEvent> {
 
-        if self.read_registers().is_ok() {
-            let gesture_id = self.blob_buf[Self::GESTURE_ID_OFF]; //TODO report gestures
-            let num_points = (self.blob_buf[Self::NUM_POINTS_OFF] & 0x0F) as usize;
-            for i in 0..num_points {
-                let evt_start: usize = (i * Self::RAW_TOUCH_EVENT_LEN) + Self::GESTURE_HEADER_LEN;
-                if let Some(mut evt) = Self::touch_event_from_data(
-                    self.blob_buf[evt_start..evt_start + Self::RAW_TOUCH_EVENT_LEN].as_ref())
-                {
-                    evt.gesture = gesture_id;
-                    //TODO we only ever appear to get one event on the PineTime: handle more?
-                    return Some(evt)
+        // the interrupt pin should be low if there is data available;
+        // otherwise, attempting to read i2c will cause a stall
+        if let Ok(data_available) = self.pin_int.is_low() {
+            if data_available {
+                if self.read_registers().is_ok() {
+                    let gesture_id = self.blob_buf[Self::GESTURE_ID_OFF];
+                    let num_points = (self.blob_buf[Self::NUM_POINTS_OFF] & 0x0F) as usize;
+                    for i in 0..num_points {
+                        let evt_start: usize = (i * Self::RAW_TOUCH_EVENT_LEN) + Self::GESTURE_HEADER_LEN;
+                        if let Some(mut evt) = Self::touch_event_from_data(
+                            self.blob_buf[evt_start..evt_start + Self::RAW_TOUCH_EVENT_LEN].as_ref())
+                        {
+                            evt.gesture = gesture_id;
+                            //TODO we only ever appear to get one event on the PineTime: handle more?
+                            return Some(evt)
+                        }
+                    }
                 }
             }
         }