altos: Get mpu6000 working

This initializes the device appropraitely, and provides a command to
dump the current values in converted form.

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

1 files changed, 202 insertions, 23 deletions

diff --git a/src/drivers/ao_mpu6000.c b/src/drivers/ao_mpu6000.c
index d7f67d6e..d27c42b0 100644
--- a/src/drivers/ao_mpu6000.c
+++ b/src/drivers/ao_mpu6000.c
@@ -23,25 +23,27 @@ static uint8_t	ao_mpu6000_wake;
 static uint8_t	ao_mpu6000_configured;
 
 static void
-ao_mpu6000_isr(void)
+ao_mpu6000_write(uint8_t addr, uint8_t *data, uint8_t len)
 {
-	ao_exti_disable(&AO_MPU6000_INT_PORT, AO_MPU6000_INT_PIN);
-	ao_mpu6000_wake = 1;
-	ao_wakeup(&ao_mpu6000_wake);
+	ao_i2c_get(AO_MPU6000_I2C_INDEX);
+	ao_i2c_start(AO_MPU6000_I2C_INDEX, MPU6000_ADDR_WRITE);
+	ao_i2c_send(&addr, 1, AO_MPU6000_I2C_INDEX, FALSE);
+	ao_i2c_send(data, len, AO_MPU6000_I2C_INDEX, TRUE);
+	ao_i2c_put(AO_MPU6000_I2C_INDEX);
 }
 
 static void
-ao_mpu6000_write(uint8_t addr, uint8_t *data, uint8_t len)
+ao_mpu6000_reg_write(uint8_t addr, uint8_t value)
 {
+	uint8_t	d[2] = { addr, value };
 	ao_i2c_get(AO_MPU6000_I2C_INDEX);
 	ao_i2c_start(AO_MPU6000_I2C_INDEX, MPU6000_ADDR_WRITE);
-	ao_i2c_send(&addr, 1, AO_MPU6000_I2C_INDEX, FALSE);
-	ao_i2c_send(data, len, AO_MPU6000_I2C_INDEX, TRUE);
+	ao_i2c_send(d, 2, AO_MPU6000_I2C_INDEX, TRUE);
 	ao_i2c_put(AO_MPU6000_I2C_INDEX);
 }
 
 static void
-ao_mpu6000_read(uint8_t addr, uint8_t *data, uint8_t len)
+ao_mpu6000_read(uint8_t addr, void *data, uint8_t len)
 {
 	ao_i2c_get(AO_MPU6000_I2C_INDEX);
 	ao_i2c_start(AO_MPU6000_I2C_INDEX, MPU6000_ADDR_WRITE);
@@ -51,34 +53,211 @@ ao_mpu6000_read(uint8_t addr, uint8_t *data, uint8_t len)
 	ao_i2c_put(AO_MPU6000_I2C_INDEX);
 }
 
+static uint8_t
+ao_mpu6000_reg_read(uint8_t addr)
+{
+	uint8_t	value;
+	ao_i2c_get(AO_MPU6000_I2C_INDEX);
+	ao_i2c_start(AO_MPU6000_I2C_INDEX, MPU6000_ADDR_WRITE);
+	ao_i2c_send(&addr, 1, AO_MPU6000_I2C_INDEX, FALSE);
+	ao_i2c_start(AO_MPU6000_I2C_INDEX, MPU6000_ADDR_READ);
+	ao_i2c_recv(&value, 1, AO_MPU6000_I2C_INDEX, TRUE);
+	ao_i2c_put(AO_MPU6000_I2C_INDEX);
+	return value;
+}
+
+static void
+ao_mpu6000_sample(struct ao_mpu6000_sample *sample)
+{
+	uint16_t	*d = (uint16_t *) sample;
+	int		i = sizeof (*sample) / 2;
+
+	ao_mpu6000_read(MPU6000_ACCEL_XOUT_H, sample, sizeof (*sample));
+	/* byte swap (sigh) */
+	while (i--) {
+		uint16_t	t = *d;
+		*d++ = (t >> 8) | (t << 8);
+	}
+}
+
+#define G	981	/* in cm/s² */
+
+static int16_t /* cm/s² */
+ao_mpu6000_accel(int16_t v)
+{
+	return (int16_t) ((v * (int32_t) (16.0 * 980.665 + 0.5)) / 32767);
+}
+
+static int16_t	/* deg*10/s */
+ao_mpu6000_gyro(int16_t v)
+{
+	return (int16_t) ((v * (int32_t) 20000) / 32767);
+}
+
+static uint8_t
+ao_mpu6000_accel_check(int16_t normal, int16_t test, char *which)
+{
+	int16_t	diff = test - normal;
+
+	if (diff < MPU6000_ST_ACCEL(16) / 2) {
+		printf ("%s accel self test value too small (normal %d, test %d)\n",
+			which, normal, test);
+		return FALSE;
+	}
+	if (diff > MPU6000_ST_ACCEL(16) * 2) {
+		printf ("%s accel self test value too large (normal %d, test %d)\n",
+			which, normal, test);
+		return FALSE;
+	}
+	return TRUE;
+}
+
+static uint8_t
+ao_mpu6000_gyro_check(int16_t normal, int16_t test, char *which)
+{
+	int16_t	diff = test - normal;
+
+	if (diff < 0)
+		diff = -diff;
+	if (diff < MPU6000_ST_GYRO(2000) / 2) {
+		printf ("%s gyro self test value too small (normal %d, test %d)\n",
+			which, normal, test);
+		return FALSE;
+	}
+	if (diff > MPU6000_ST_GYRO(2000) * 2) {
+		printf ("%s gyro self test value too large (normal %d, test %d)\n",
+			which, normal, test);
+		return FALSE;
+	}
+	return TRUE;
+}
+
 static void
 ao_mpu6000_setup(void)
 {
+	struct ao_mpu6000_sample	normal_mode, test_mode;
+	int				t;
+
 	if (ao_mpu6000_configured)
 		return;
 
-	/* Enable the EXTI interrupt for the appropriate pin */
-	ao_enable_port(AO_MPU6000_INT_PORT);
-	ao_exti_setup(&AO_MPU6000_INT_PORT, AO_MPU6000_INT_PIN,
-		      AO_EXTI_MODE_FALLING, ao_mpu6000_isr);
+	/* Reset the whole chip */
+	
+	ao_mpu6000_reg_write(MPU6000_PWR_MGMT_1,
+			     (1 << MPU6000_PWR_MGMT_1_DEVICE_RESET));
+	while (ao_mpu6000_reg_read(MPU6000_PWR_MGMT_1) &
+	       (1 << MPU6000_PWR_MGMT_1_DEVICE_RESET))
+		ao_yield();
+
+	/* Reset signal conditioning */
+	ao_mpu6000_reg_write(MPU6000_USER_CONTROL,
+			     (0 << MPU6000_USER_CONTROL_FIFO_EN) |
+			     (0 << MPU6000_USER_CONTROL_I2C_MST_EN) |
+			     (0 << MPU6000_USER_CONTROL_I2C_IF_DIS) |
+			     (0 << MPU6000_USER_CONTROL_FIFO_RESET) |
+			     (0 << MPU6000_USER_CONTROL_I2C_MST_RESET) |
+			     (1 << MPU6000_USER_CONTROL_SIG_COND_RESET));
+
+	while (ao_mpu6000_reg_read(MPU6000_USER_CONTROL) & (1 << MPU6000_USER_CONTROL_SIG_COND_RESET))
+		ao_yield();
+
+	/* Reset signal paths */
+	ao_mpu6000_reg_write(MPU6000_SIGNAL_PATH_RESET,
+			     (1 << MPU6000_SIGNAL_PATH_RESET_GYRO_RESET) |
+			     (1 << MPU6000_SIGNAL_PATH_RESET_ACCEL_RESET) |
+			     (1 << MPU6000_SIGNAL_PATH_RESET_TEMP_RESET));
+
+	ao_mpu6000_reg_write(MPU6000_SIGNAL_PATH_RESET,
+			     (0 << MPU6000_SIGNAL_PATH_RESET_GYRO_RESET) |
+			     (0 << MPU6000_SIGNAL_PATH_RESET_ACCEL_RESET) |
+			     (0 << MPU6000_SIGNAL_PATH_RESET_TEMP_RESET));
 
+	/* Select clocks, disable sleep */
+	ao_mpu6000_reg_write(MPU6000_PWR_MGMT_1,
+			     (0 << MPU6000_PWR_MGMT_1_DEVICE_RESET) |
+			     (0 << MPU6000_PWR_MGMT_1_SLEEP) |
+			     (0 << MPU6000_PWR_MGMT_1_CYCLE) |
+			     (0 << MPU6000_PWR_MGMT_1_TEMP_DIS) |
+			     (MPU6000_PWR_MGMT_1_CLKSEL_PLL_X_AXIS << MPU6000_PWR_MGMT_1_CLKSEL));
+
+	/* Set sample rate divider to sample at full speed
+	ao_mpu6000_reg_write(MPU6000_SMPRT_DIV, 0);
+
+	/* Disable filtering */
+	ao_mpu6000_reg_write(MPU6000_CONFIG,
+			     (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);
+
+	/* 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);
+	
+	ao_mpu6000_accel_check(normal_mode.accel_x, test_mode.accel_x, "x");
+	ao_mpu6000_accel_check(normal_mode.accel_y, test_mode.accel_y, "y");
+	ao_mpu6000_accel_check(normal_mode.accel_z, test_mode.accel_z, "z");
+
+	ao_mpu6000_gyro_check(normal_mode.gyro_x, test_mode.gyro_x, "x");
+	ao_mpu6000_gyro_check(normal_mode.gyro_y, test_mode.gyro_y, "y");
+	ao_mpu6000_gyro_check(normal_mode.gyro_z, test_mode.gyro_z, "z");
+
+	/* Filter to about 100Hz, which also sets the gyro rate to 1000Hz */
+	ao_mpu6000_reg_write(MPU6000_CONFIG,
+			     (MPU6000_CONFIG_EXT_SYNC_SET_DISABLED << MPU6000_CONFIG_EXT_SYNC_SET) |
+			     (MPU6000_CONFIG_DLPF_CFG_94_98 << MPU6000_CONFIG_DLPF_CFG));
+
+	/* Set sample rate divider to sample at 200Hz (v = gyro/rate - 1) */
+	ao_mpu6000_reg_write(MPU6000_SMPRT_DIV,
+			     1000 / 200 - 1);
+	
+	ao_delay(AO_MS_TO_TICKS(100));
 	ao_mpu6000_configured = 1;
 }
 
+
 static void
 ao_mpu6000_show(void)
 {
-	uint8_t	addr;
-	uint8_t	data[14];
-	uint8_t i;
-
-	ao_mpu6000_read(MPU6000_WHO_AM_I, data, 1);
-	printf ("mpu6000 WHO_AM_I: %02x\n", data[0]);
-#if 0
-	ao_mpu6000_read(MPU6000_ACCEL_XOUT_H, data, 14);
-	for (i = 0; i < 14; i++)
-		printf ("reg %02x: %02x\n", i + MPU6000_ACCEL_XOUT_H, data[i]);
-#endif
+	struct ao_mpu6000_sample	sample;
+
+	ao_mpu6000_setup();
+	ao_mpu6000_sample(&sample);
+	printf ("Accel: %7d %7d %7d Gyro: %7d %7d %7d\n",
+		ao_mpu6000_accel(sample.accel_x),
+		ao_mpu6000_accel(sample.accel_y),
+		ao_mpu6000_accel(sample.accel_z),
+		ao_mpu6000_gyro(sample.gyro_x),
+		ao_mpu6000_gyro(sample.gyro_y),
+		ao_mpu6000_gyro(sample.gyro_z));
 }
 
 static const struct ao_cmds ao_mpu6000_cmds[] = {