accelerometer: don't initialize on wake if already set up

diff --git a/movement.c b/movement.c
index cafa09fcc10867415e92b459a826ee9ad78f990d..25de0598c923df7f6c20387257411d2aededfa7d 100644 (file)
--- a/movement.c
+++ b/movement.c
@@ -716,50 +716,53 @@ void app_setup(void) {
         watch_register_interrupt_callback(HAL_GPIO_BTN_ALARM_pin(), cb_alarm_btn_interrupt, INTERRUPT_TRIGGER_BOTH);
 
 #ifdef I2C_SERCOM
-        watch_enable_i2c();
-        if (lis2dw_begin()) {
-            movement_state.has_lis2dw = true;
-
-            lis2dw_set_mode(LIS2DW_MODE_LOW_POWER);         // select low power (not high performance) mode
-            lis2dw_set_low_power_mode(LIS2DW_LP_MODE_1);    // lowest power mode, 12-bit
-            lis2dw_set_low_noise_mode(false);               // low noise mode raises power consumption slightly; we don't need it
-            lis2dw_enable_stationary_motion_detection();    // stationary/motion detection mode keeps the data rate at 1.6 Hz even in sleep
-            lis2dw_set_range(LIS2DW_RANGE_2_G);             // Application note AN5038 recommends 2g range
-            lis2dw_enable_sleep();                          // allow acceleromter to sleep and wake on activity
-            lis2dw_configure_wakeup_threshold(32);          // g threshold to wake up: (THS * FS / 64) where FS is "full scale" of ±2g.
-            lis2dw_configure_6d_threshold(3);               // 0-3 is 80, 70, 60, or 50 degrees. 50 is least precise, hopefully most sensitive?
-
-            // set up interrupts:
-            // INT1 is wired to pin A3. We'll configure the accelerometer to output an interrupt on INT1 when it detects an orientation change.
-            /// TODO: We had routed this interrupt to TC2 to count orientation changes, but TC2 consumed too much power.
-            /// Orientation changes helped with sleep tracking; would love to bring this back if we can find a low power solution.
-            /// For now, commenting these lines out; check commit 27f0c629d865f4bc56bc6e678da1eb8f4b919093 for power-hungry but working code.
-            // lis2dw_configure_int1(LIS2DW_CTRL4_INT1_6D);
-            // HAL_GPIO_A3_in();
-
-            // next: INT2 is wired to pin A4. We'll configure the accelerometer to output the sleep state on INT2.
-            // a falling edge on INT2 indicates the accelerometer has woken up.
-            lis2dw_configure_int2(LIS2DW_CTRL5_INT2_SLEEP_STATE | LIS2DW_CTRL5_INT2_SLEEP_CHG);
-            HAL_GPIO_A4_in();
-
-            // Wake on motion seemed like a good idea when the threshold was lower, but the UX makes less sense now.
-            // Still if you want to wake on motion, you can do it by uncommenting this line:
-            // watch_register_extwake_callback(HAL_GPIO_A4_pin(), cb_accelerometer_wake, false);
-
-            // later on, we are going to use INT1 for tap detection. We'll set up that interrupt here,
-            // but it will only fire once tap recognition is enabled.
-            watch_register_interrupt_callback(HAL_GPIO_A3_pin(), cb_accelerometer_event, INTERRUPT_TRIGGER_RISING);
-
-            // Enable the interrupts...
-            lis2dw_enable_interrupts();
-
-            // ...and power down the accelerometer to save energy. This means the interrupts we just configured won't fire.
-            // Tap detection will ramp up sesing and make use of the A3 interrupt.
-            // If a watch face wants to check in on the A4 pin, it can call movement_set_accelerometer_background_rate
-            lis2dw_set_data_rate(LIS2DW_DATA_RATE_POWERDOWN);
-            movement_state.accelerometer_background_rate = LIS2DW_DATA_RATE_POWERDOWN;
-        } else {
-            watch_disable_i2c();
+        // if accelerometer was already detected and set up, no need to set it up again.
+        if (!movement_state.has_lis2dw) {
+            watch_enable_i2c();
+            if (lis2dw_begin()) {
+                movement_state.has_lis2dw = true;
+
+                lis2dw_set_mode(LIS2DW_MODE_LOW_POWER);         // select low power (not high performance) mode
+                lis2dw_set_low_power_mode(LIS2DW_LP_MODE_1);    // lowest power mode, 12-bit
+                lis2dw_set_low_noise_mode(false);               // low noise mode raises power consumption slightly; we don't need it
+                lis2dw_enable_stationary_motion_detection();    // stationary/motion detection mode keeps the data rate at 1.6 Hz even in sleep
+                lis2dw_set_range(LIS2DW_RANGE_2_G);             // Application note AN5038 recommends 2g range
+                lis2dw_enable_sleep();                          // allow acceleromter to sleep and wake on activity
+                lis2dw_configure_wakeup_threshold(32);          // g threshold to wake up: (THS * FS / 64) where FS is "full scale" of ±2g.
+                lis2dw_configure_6d_threshold(3);               // 0-3 is 80, 70, 60, or 50 degrees. 50 is least precise, hopefully most sensitive?
+
+                // set up interrupts:
+                // INT1 is wired to pin A3. We'll configure the accelerometer to output an interrupt on INT1 when it detects an orientation change.
+                /// TODO: We had routed this interrupt to TC2 to count orientation changes, but TC2 consumed too much power.
+                /// Orientation changes helped with sleep tracking; would love to bring this back if we can find a low power solution.
+                /// For now, commenting these lines out; check commit 27f0c629d865f4bc56bc6e678da1eb8f4b919093 for power-hungry but working code.
+                // lis2dw_configure_int1(LIS2DW_CTRL4_INT1_6D);
+                // HAL_GPIO_A3_in();
+
+                // next: INT2 is wired to pin A4. We'll configure the accelerometer to output the sleep state on INT2.
+                // a falling edge on INT2 indicates the accelerometer has woken up.
+                lis2dw_configure_int2(LIS2DW_CTRL5_INT2_SLEEP_STATE | LIS2DW_CTRL5_INT2_SLEEP_CHG);
+                HAL_GPIO_A4_in();
+
+                // Wake on motion seemed like a good idea when the threshold was lower, but the UX makes less sense now.
+                // Still if you want to wake on motion, you can do it by uncommenting this line:
+                // watch_register_extwake_callback(HAL_GPIO_A4_pin(), cb_accelerometer_wake, false);
+
+                // later on, we are going to use INT1 for tap detection. We'll set up that interrupt here,
+                // but it will only fire once tap recognition is enabled.
+                watch_register_interrupt_callback(HAL_GPIO_A3_pin(), cb_accelerometer_event, INTERRUPT_TRIGGER_RISING);
+
+                // Enable the interrupts...
+                lis2dw_enable_interrupts();
+
+                // ...and power down the accelerometer to save energy. This means the interrupts we just configured won't fire.
+                // Tap detection will ramp up sesing and make use of the A3 interrupt.
+                // If a watch face wants to check in on the A4 pin, it can call movement_set_accelerometer_background_rate
+                lis2dw_set_data_rate(LIS2DW_DATA_RATE_POWERDOWN);
+                movement_state.accelerometer_background_rate = LIS2DW_DATA_RATE_POWERDOWN;
+            } else {
+                watch_disable_i2c();
+            }
         }
 #endif