altos: Fix TMega v6.0 and v5.0 IMU axes

[fw/altos] / src / telemega-v5.0 / ao_pins.h

diff --git a/src/telemega-v5.0/ao_pins.h b/src/telemega-v5.0/ao_pins.h
index 3f2c9ea44e5365a8c7862499c874b21a8c6a7d50..01774519f2cc1b461468b47860d8b323400855d9 100644 (file)
--- a/src/telemega-v5.0/ao_pins.h
+++ b/src/telemega-v5.0/ao_pins.h
@@ -329,22 +329,27 @@ struct ao_adc {
 
 
 /*
+ * Here are the required sensor signs:
  *
- * If the board is laying component side up with
- * the antenna (nose) pointing north
+ * +along      nose up
+ * +across     USB down
+ * +through    TH down
  *
- * +along      north   +roll   left up
- * +across     west    +pitch  nose down
- * +through    up      +yaw    left turn
+ * With the board aligned to have positive accel for the relevant
+ * axis, looking down from above we have:
+ *
+ * +roll       counter clockwise (nose up)
+ * +pitch      counter clockwise (USB down)
+ * +yaw                counter clockwise (TH down)
  */
 
 /*
- * mpu6000
- *
- *     pin 1 NW corner of chip
+ * On TMega v5, MPU6000 pin 1 (NW corner of chip) is placed towards
+ * the USB and antenna edges of the board. Relative to MPU6000 specs,
+ * we don't need to change any signs and so the correct values are:
  *
  *     +along          +Y      +roll   +Y
- *     +across         -X      +pitch  -X
+ *     +across         +X      +pitch  +X
  *     +through        +Z      +yaw    +Z
  *
  */
@@ -358,11 +363,11 @@ struct ao_adc {
 #define HAS_IMU                        1
 
 #define ao_mpu6000_along(m)    ((m)->accel_y)
-#define ao_mpu6000_across(m)   (-(m)->accel_x)
+#define ao_mpu6000_across(m)   ((m)->accel_x)
 #define ao_mpu6000_through(m)  ((m)->accel_z)
 
 #define ao_mpu6000_roll(m)     ((m)->gyro_y)
-#define ao_mpu6000_pitch(m)    (-(m)->gyro_x)
+#define ao_mpu6000_pitch(m)    ((m)->gyro_x)
 #define ao_mpu6000_yaw(m)      ((m)->gyro_z)
 
 #define ao_data_along(packet)  ao_mpu6000_along(&(packet)->mpu6000)