altos: Try IMU self-test 10 times before giving up

This should keep the device from failing to boot unless the IMU is
actually broken. Oh, and if self test does fail, this places the
flight computer in 'Invalid' state rather than panic.

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 56 insertions, 48 deletions

diff --git a/src/drivers/ao_mpu6000.c b/src/drivers/ao_mpu6000.c
index 5e75b78a..f8ce7346 100644
--- a/src/drivers/ao_mpu6000.c
+++ b/src/drivers/ao_mpu6000.c
@@ -137,10 +137,10 @@ ao_mpu6000_accel_check(int16_t normal, int16_t test, char *which)
 {
 	int16_t	diff = test - normal;
 
-	if (diff < MPU6000_ST_ACCEL(16) / 2) {
+	if (diff < MPU6000_ST_ACCEL(16) / 4) {
 		return 1;
 	}
-	if (diff > MPU6000_ST_ACCEL(16) * 2) {
+	if (diff > MPU6000_ST_ACCEL(16) * 4) {
 		return 1;
 	}
 	return 0;
@@ -153,10 +153,10 @@ ao_mpu6000_gyro_check(int16_t normal, int16_t test, char *which)
 
 	if (diff < 0)
 		diff = -diff;
-	if (diff < MPU6000_ST_GYRO(2000) / 2) {
+	if (diff < MPU6000_ST_GYRO(2000) / 4) {
 		return 1;
 	}
-	if (diff > MPU6000_ST_GYRO(2000) * 2) {
+	if (diff > MPU6000_ST_GYRO(2000) * 4) {
 		return 1;
 	}
 	return 0;
@@ -177,11 +177,14 @@ _ao_mpu6000_wait_alive(void)
 		ao_panic(AO_PANIC_SELF_TEST_MPU6000);
 }
 
+#define ST_TRIES	10
+
 static void
 _ao_mpu6000_setup(void)
 {
 	struct ao_mpu6000_sample	normal_mode, test_mode;
-	int				errors =0;
+	int				errors;
+	int				st_tries;
 
 	if (ao_mpu6000_configured)
 		return;
@@ -236,23 +239,6 @@ _ao_mpu6000_setup(void)
 			      (MPU6000_CONFIG_EXT_SYNC_SET_DISABLED << MPU6000_CONFIG_EXT_SYNC_SET) |
 			      (MPU6000_CONFIG_DLPF_CFG_260_256 << MPU6000_CONFIG_DLPF_CFG));
 
-	/* Configure accelerometer to +/-16G in self-test mode */
-	_ao_mpu6000_reg_write(MPU6000_ACCEL_CONFIG,
-			      (1 << MPU600_ACCEL_CONFIG_XA_ST) |
-			      (1 << MPU600_ACCEL_CONFIG_YA_ST) |
-			      (1 << MPU600_ACCEL_CONFIG_ZA_ST) |
-			      (MPU600_ACCEL_CONFIG_AFS_SEL_16G << MPU600_ACCEL_CONFIG_AFS_SEL));
-
-	/* Configure gyro to +/- 2000°/s in self-test mode */
-	_ao_mpu6000_reg_write(MPU6000_GYRO_CONFIG,
-			      (1 << MPU600_GYRO_CONFIG_XG_ST) |
-			      (1 << MPU600_GYRO_CONFIG_YG_ST) |
-			      (1 << MPU600_GYRO_CONFIG_ZG_ST) |
-			      (MPU600_GYRO_CONFIG_FS_SEL_2000 << MPU600_GYRO_CONFIG_FS_SEL));
-
-	ao_delay(AO_MS_TO_TICKS(200));
-	_ao_mpu6000_sample(&test_mode);
-
 #if TRIDGE
 	// read the product ID rev c has 1/2 the sensitivity of rev d
 	_mpu6000_product_id = _register_read(MPUREG_PRODUCT_ID);
@@ -268,36 +254,58 @@ _ao_mpu6000_setup(void)
 		register_write(MPUREG_ACCEL_CONFIG,2<<3);
 	}
 	hal.scheduler->delay(1);
-
 #endif
 
-	/* Configure accelerometer to +/-16G */
-	_ao_mpu6000_reg_write(MPU6000_ACCEL_CONFIG,
-			      (0 << MPU600_ACCEL_CONFIG_XA_ST) |
-			      (0 << MPU600_ACCEL_CONFIG_YA_ST) |
-			      (0 << MPU600_ACCEL_CONFIG_ZA_ST) |
-			      (MPU600_ACCEL_CONFIG_AFS_SEL_16G << MPU600_ACCEL_CONFIG_AFS_SEL));
-
-	/* Configure gyro to +/- 2000°/s */
-	_ao_mpu6000_reg_write(MPU6000_GYRO_CONFIG,
-			      (0 << MPU600_GYRO_CONFIG_XG_ST) |
-			      (0 << MPU600_GYRO_CONFIG_YG_ST) |
-			      (0 << MPU600_GYRO_CONFIG_ZG_ST) |
-			      (MPU600_GYRO_CONFIG_FS_SEL_2000 << MPU600_GYRO_CONFIG_FS_SEL));
-
-	ao_delay(AO_MS_TO_TICKS(10));
-	_ao_mpu6000_sample(&normal_mode);
+	for (st_tries = 0; st_tries < ST_TRIES; st_tries++) {
+		errors = 0;
+
+		/* Configure accelerometer to +/-16G in self-test mode */
+		_ao_mpu6000_reg_write(MPU6000_ACCEL_CONFIG,
+				      (1 << MPU600_ACCEL_CONFIG_XA_ST) |
+				      (1 << MPU600_ACCEL_CONFIG_YA_ST) |
+				      (1 << MPU600_ACCEL_CONFIG_ZA_ST) |
+				      (MPU600_ACCEL_CONFIG_AFS_SEL_16G << MPU600_ACCEL_CONFIG_AFS_SEL));
+
+		/* Configure gyro to +/- 2000°/s in self-test mode */
+		_ao_mpu6000_reg_write(MPU6000_GYRO_CONFIG,
+				      (1 << MPU600_GYRO_CONFIG_XG_ST) |
+				      (1 << MPU600_GYRO_CONFIG_YG_ST) |
+				      (1 << MPU600_GYRO_CONFIG_ZG_ST) |
+				      (MPU600_GYRO_CONFIG_FS_SEL_2000 << MPU600_GYRO_CONFIG_FS_SEL));
+
+		ao_delay(AO_MS_TO_TICKS(200));
+		_ao_mpu6000_sample(&test_mode);
+
+		/* Configure accelerometer to +/-16G */
+		_ao_mpu6000_reg_write(MPU6000_ACCEL_CONFIG,
+				      (0 << MPU600_ACCEL_CONFIG_XA_ST) |
+				      (0 << MPU600_ACCEL_CONFIG_YA_ST) |
+				      (0 << MPU600_ACCEL_CONFIG_ZA_ST) |
+				      (MPU600_ACCEL_CONFIG_AFS_SEL_16G << MPU600_ACCEL_CONFIG_AFS_SEL));
+
+		/* Configure gyro to +/- 2000°/s */
+		_ao_mpu6000_reg_write(MPU6000_GYRO_CONFIG,
+				      (0 << MPU600_GYRO_CONFIG_XG_ST) |
+				      (0 << MPU600_GYRO_CONFIG_YG_ST) |
+				      (0 << MPU600_GYRO_CONFIG_ZG_ST) |
+				      (MPU600_GYRO_CONFIG_FS_SEL_2000 << MPU600_GYRO_CONFIG_FS_SEL));
+
+		ao_delay(AO_MS_TO_TICKS(200));
+		_ao_mpu6000_sample(&normal_mode);
 	
-	errors += ao_mpu6000_accel_check(normal_mode.accel_x, test_mode.accel_x, "x");
-	errors += ao_mpu6000_accel_check(normal_mode.accel_y, test_mode.accel_y, "y");
-	errors += ao_mpu6000_accel_check(normal_mode.accel_z, test_mode.accel_z, "z");
-
-	errors += ao_mpu6000_gyro_check(normal_mode.gyro_x, test_mode.gyro_x, "x");
-	errors += ao_mpu6000_gyro_check(normal_mode.gyro_y, test_mode.gyro_y, "y");
-	errors += ao_mpu6000_gyro_check(normal_mode.gyro_z, test_mode.gyro_z, "z");
+		errors += ao_mpu6000_accel_check(normal_mode.accel_x, test_mode.accel_x, "x");
+		errors += ao_mpu6000_accel_check(normal_mode.accel_y, test_mode.accel_y, "y");
+		errors += ao_mpu6000_accel_check(normal_mode.accel_z, test_mode.accel_z, "z");
+
+		errors += ao_mpu6000_gyro_check(normal_mode.gyro_x, test_mode.gyro_x, "x");
+		errors += ao_mpu6000_gyro_check(normal_mode.gyro_y, test_mode.gyro_y, "y");
+		errors += ao_mpu6000_gyro_check(normal_mode.gyro_z, test_mode.gyro_z, "z");
+		if (!errors)
+			break;
+	}
 
-	if (errors)
-		ao_panic(AO_PANIC_SELF_TEST_MPU6000);
+	if (st_tries == ST_TRIES)
+		ao_sensor_errors = 1;
 
 	/* Filter to about 100Hz, which also sets the gyro rate to 1000Hz */
 	_ao_mpu6000_reg_write(MPU6000_CONFIG,