#define ACCEL_VEL_MACH VEL_MPS_TO_COUNT(200)
#define ACCEL_VEL_BOOST VEL_MPS_TO_COUNT(5)
-int32_t accel_vel_mach;
-int32_t accel_vel_boost;
-
/*
* Barometer calibration
*
ao_raw_pres = 0;
ao_flight_tick = 0;
for (;;) {
- ao_sleep(&ao_adc_ring);
+ ao_wakeup(DATA_TO_XDATA(&ao_flight_adc));
+ ao_sleep(DATA_TO_XDATA(&ao_adc_head));
while (ao_flight_adc != ao_adc_head) {
__pdata uint8_t ticks;
__pdata int16_t ao_vel_change;
+ __xdata struct ao_adc *ao_adc;
ao_flight_prev_tick = ao_flight_tick;
/* Capture a sample */
- ao_raw_accel = ao_adc_ring[ao_flight_adc].accel;
- ao_raw_pres = ao_adc_ring[ao_flight_adc].pres;
- ao_flight_tick = ao_adc_ring[ao_flight_adc].tick;
+ ao_adc = &ao_adc_ring[ao_flight_adc];
+ ao_flight_tick = ao_adc->tick;
+ ao_raw_accel = ao_adc->accel;
+#if HAS_ACCEL_REF
+ /*
+ * Ok, the math here is a bit tricky.
+ *
+ * ao_raw_accel: ADC output for acceleration
+ * ao_accel_ref: ADC output for the 5V reference.
+ * ao_cook_accel: Corrected acceleration value
+ * Vcc: 3.3V supply to the CC1111
+ * Vac: 5V supply to the accelerometer
+ * accel: input voltage to accelerometer ADC pin
+ * ref: input voltage to 5V reference ADC pin
+ *
+ *
+ * Measured acceleration is ratiometric to Vcc:
+ *
+ * ao_raw_accel accel
+ * ------------ = -----
+ * 32767 Vcc
+ *
+ * Measured 5v reference is also ratiometric to Vcc:
+ *
+ * ao_accel_ref ref
+ * ------------ = -----
+ * 32767 Vcc
+ *
+ *
+ * ao_accel_ref = 32767 * (ref / Vcc)
+ *
+ * Acceleration is measured ratiometric to the 5V supply,
+ * so what we want is:
+ *
+ * ao_cook_accel accel
+ * ------------- = -----
+ * 32767 ref
+ *
+ *
+ * accel Vcc
+ * = ----- * ---
+ * Vcc ref
+ *
+ * ao_raw_accel 32767
+ * = ------------ * ------------
+ * 32737 ao_accel_ref
+ *
+ * Multiply through by 32767:
+ *
+ * ao_raw_accel * 32767
+ * ao_cook_accel = --------------------
+ * ao_accel_ref
+ *
+ * Now, the tricky part. Getting this to compile efficiently
+ * and keeping all of the values in-range.
+ *
+ * First off, we need to use a shift of 16 instead of * 32767 as SDCC
+ * does the obvious optimizations for byte-granularity shifts:
+ *
+ * ao_cook_accel = (ao_raw_accel << 16) / ao_accel_ref
+ *
+ * Next, lets check our input ranges:
+ *
+ * 0 <= ao_raw_accel <= 0x7fff (singled ended ADC conversion)
+ * 0x7000 <= ao_accel_ref <= 0x7fff (the 5V ref value is close to 0x7fff)
+ *
+ * Plugging in our input ranges, we get an output range of 0 - 0x12490,
+ * which is 17 bits. That won't work. If we take the accel ref and shift
+ * by a bit, we'll change its range:
+ *
+ * 0xe000 <= ao_accel_ref<<1 <= 0xfffe
+ *
+ * ao_cook_accel = (ao_raw_accel << 16) / (ao_accel_ref << 1)
+ *
+ * Now the output range is 0 - 0x9248, which nicely fits in 16 bits. It
+ * is, however, one bit too large for our signed computations. So, we
+ * take the result and shift that by a bit:
+ *
+ * ao_cook_accel = ((ao_raw_accel << 16) / (ao_accel_ref << 1)) >> 1
+ *
+ * This finally creates an output range of 0 - 0x4924. As the ADC only
+ * provides 11 bits of data, we haven't actually lost any precision,
+ * just dropped a bit of noise off the low end.
+ */
+ ao_raw_accel = (uint16_t) ((((uint32_t) ao_raw_accel << 16) / (ao_accel_ref[ao_flight_adc] << 1))) >> 1;
+ ao_adc->accel = ao_raw_accel;
+#endif
+ ao_raw_pres = ao_adc->pres;
ao_flight_accel -= ao_flight_accel >> 4;
ao_flight_accel += ao_raw_accel >> 4;
/* startup state:
*
- * Collect 1000 samples of acceleration and pressure
+ * Collect 512 samples of acceleration and pressure
* data and average them to find the resting values
*/
- if (nsamples < 1000) {
+ if (nsamples < 512) {
ao_raw_accel_sum += ao_raw_accel;
ao_raw_pres_sum += ao_raw_pres;
++nsamples;
continue;
}
- ao_ground_accel = (ao_raw_accel_sum / nsamples);
- ao_ground_pres = (ao_raw_pres_sum / nsamples);
+ ao_ground_accel = ao_raw_accel_sum >> 9;
+ ao_ground_pres = ao_raw_pres_sum >> 9;
ao_min_pres = ao_ground_pres;
ao_config_get();
ao_main_pres = ao_altitude_to_pres(ao_pres_to_altitude(ao_ground_pres) + ao_config.main_deploy);
ao_accel_2g = ao_config.accel_minus_g - ao_config.accel_plus_g;
- accel_vel_mach = ACCEL_VEL_MACH;
- accel_vel_boost = ACCEL_VEL_BOOST;
ao_flight_vel = 0;
ao_min_vel = 0;
ao_old_vel = ao_flight_vel;
ao_old_vel_tick = ao_flight_tick;
- /* Go to pad state if the nose is pointing up */
+ /* Check to see what mode we should go to.
+ * - Invalid mode if accel cal appears to be out
+ * - pad mode if we're upright,
+ * - idle mode otherwise
+ */
ao_config_get();
- if (ao_config.accel_plus_g != 0 &&
- ao_config.accel_minus_g != 0 &&
- ao_flight_accel < ao_config.accel_plus_g + ACCEL_NOSE_UP &&
- !ao_flight_force_idle)
+ if (ao_config.accel_plus_g == 0 ||
+ ao_config.accel_minus_g == 0 ||
+ ao_flight_accel < ao_config.accel_plus_g - ACCEL_NOSE_UP ||
+ ao_flight_accel > ao_config.accel_minus_g + ACCEL_NOSE_UP)
{
+ /* Detected an accel value outside -1.5g to 1.5g
+ * (or uncalibrated values), so we go into invalid mode
+ */
+ ao_flight_state = ao_flight_invalid;
+ /* Allow packet mode in invalid flight state,
+ * Still need to be able to fix the problem!
+ */
+ ao_packet_slave_start();
+
+ } else if (ao_flight_accel < ao_config.accel_plus_g + ACCEL_NOSE_UP &&
+ !ao_flight_force_idle)
+ {
+ /* Set pad mode - we can fly! */
+ ao_flight_state = ao_flight_pad;
+
/* Disable the USB controller in flight mode
* to save power
*/
ao_usb_disable();
- /* Turn on telemetry system
- */
+ /* Turn on telemetry system */
ao_rdf_set(1);
ao_telemetry_set_interval(AO_TELEMETRY_INTERVAL_PAD);
- ao_flight_state = ao_flight_pad;
- ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
+ /* signal successful initialization by turning off the LED */
+ ao_led_off(AO_LED_RED);
} else {
- ao_flight_state = ao_flight_idle;
-
- /* Turn on packet system in idle mode
- */
+ /* Set idle mode */
+ ao_flight_state = ao_flight_idle;
+
+ /* Turn on packet system in idle mode */
ao_packet_slave_start();
- ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
+
+ /* signal successful initialization by turning off the LED */
+ ao_led_off(AO_LED_RED);
}
- /* signal successful initialization by turning off the LED */
- ao_led_off(AO_LED_RED);
+ /* wakeup threads due to state change */
+ ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
+
break;
case ao_flight_pad:
/* disable RDF beacon */
ao_rdf_set(0);
+ /* Record current GPS position by waking up GPS log tasks */
+ ao_wakeup(&ao_gps_data);
+ ao_wakeup(&ao_gps_tracking_data);
+
ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
break;
}
ao_flight_init(void)
{
ao_flight_state = ao_flight_startup;
- ao_interval_min_accel = 0;
- ao_interval_max_accel = 0x7fff;
- ao_interval_min_pres = 0;
- ao_interval_max_pres = 0x7fff;
- ao_interval_end = AO_INTERVAL_TICKS;
-
ao_add_task(&flight_task, ao_flight, "flight");
}
projects / fw / altos / blobdiff