/* Main flight thread. */
__pdata enum ao_flight_state ao_flight_state; /* current flight state */
-__pdata uint16_t ao_flight_tick; /* time of last data */
-__pdata uint16_t ao_flight_prev_tick; /* time of previous data */
-__xdata int16_t ao_ground_pres; /* startup pressure */
__pdata uint16_t ao_launch_tick; /* time of launch detect */
-#if HAS_ACCEL
-__pdata int16_t ao_ground_accel; /* startup acceleration */
-#endif
/*
* track min/max data over a long interval to detect
__pdata int16_t ao_interval_min_height;
__pdata int16_t ao_interval_max_height;
-__data uint8_t ao_flight_adc;
-__pdata int16_t ao_raw_pres;
-__xdata uint8_t ao_flight_force_idle;
-
-#if HAS_ACCEL
-__pdata int16_t ao_raw_accel, ao_raw_accel_prev;
-__pdata int16_t ao_accel_2g;
-
-/* Accelerometer calibration
- *
- * We're sampling the accelerometer through a resistor divider which
- * consists of 5k and 10k resistors. This multiplies the values by 2/3.
- * That goes into the cc1111 A/D converter, which is running at 11 bits
- * of precision with the bits in the MSB of the 16 bit value. Only positive
- * values are used, so values should range from 0-32752 for 0-3.3V. The
- * specs say we should see 40mV/g (uncalibrated), multiply by 2/3 for what
- * the A/D converter sees (26.67 mV/g). We should see 32752/3300 counts/mV,
- * for a final computation of:
- *
- * 26.67 mV/g * 32767/3300 counts/mV = 264.8 counts/g
- *
- * Zero g was measured at 16000 (we would expect 16384).
- * Note that this value is only require to tell if the
- * rocket is standing upright. Once that is determined,
- * the value of the accelerometer is averaged for 100 samples
- * to find the resting accelerometer value, which is used
- * for all further flight computations
- */
-
-#define GRAVITY 9.80665
-
-#define ACCEL_NOSE_UP (ao_accel_2g >> 2)
-
-#endif
-
-/*
- * Barometer calibration
- *
- * We directly sample the barometer. The specs say:
- *
- * Pressure range: 15-115 kPa
- * Voltage at 115kPa: 2.82
- * Output scale: 27mV/kPa
- *
- * If we want to detect launch with the barometer, we need
- * a large enough bump to not be fooled by noise. At typical
- * launch elevations (0-2000m), a 200Pa pressure change cooresponds
- * to about a 20m elevation change. This is 5.4mV, or about 3LSB.
- * As all of our calculations are done in 16 bits, we'll actually see a change
- * of 16 times this though
- *
- * 27 mV/kPa * 32767 / 3300 counts/mV = 268.1 counts/kPa
- */
+__xdata uint8_t ao_flight_force_idle;
/* We also have a clock, which can be used to sanity check things in
* case of other failures
#define BOOST_TICKS_MAX AO_SEC_TO_TICKS(15)
-#define to_fix16(x) ((int16_t) ((x) * 65536.0 + 0.5))
-#define to_fix32(x) ((int32_t) ((x) * 65536.0 + 0.5))
-#define from_fix(x) ((x) >> 16)
-
-#include "ao_kalman.h"
-
-__pdata int16_t ao_ground_height;
-__pdata int16_t ao_height;
-__pdata int16_t ao_speed;
-__pdata int16_t ao_accel;
-__pdata int16_t ao_max_height;
-
-static __pdata int32_t ao_k_height;
-static __pdata int32_t ao_k_speed;
-static __pdata int32_t ao_k_accel;
-
-#define AO_K_STEP_100 to_fix16(0.01)
-#define AO_K_STEP_2_2_100 to_fix16(0.00005)
-
-#define AO_K_STEP_10 to_fix16(0.1)
-#define AO_K_STEP_2_2_10 to_fix16(0.005)
-
-/*
- * Above this height, the baro sensor doesn't work
- */
-#define AO_MAX_BARO_HEIGHT 12000
-
-/*
- * Above this speed, baro measurements are unreliable
- */
-#define AO_MAX_BARO_SPEED 200
-
-static void
-ao_kalman_predict(void)
-{
-#ifdef AO_FLIGHT_TEST
- if (ao_flight_tick - ao_flight_prev_tick > 5) {
- ao_k_height += ((int32_t) ao_speed * AO_K_STEP_10 +
- (int32_t) ao_accel * AO_K_STEP_2_2_10) >> 4;
- ao_k_speed += (int32_t) ao_accel * AO_K_STEP_10;
-
- return;
- }
- if (ao_flight_debug) {
- printf ("predict speed %g + (%g * %g) = %g\n",
- ao_k_speed / (65536.0 * 16.0), ao_accel / 16.0, AO_K_STEP_100 / 65536.0,
- (ao_k_speed + (int32_t) ao_accel * AO_K_STEP_100) / (65536.0 * 16.0));
- }
-#endif
- ao_k_height += ((int32_t) ao_speed * AO_K_STEP_100 +
- (int32_t) ao_accel * AO_K_STEP_2_2_100) >> 4;
- ao_k_speed += (int32_t) ao_accel * AO_K_STEP_100;
-}
-
-static __pdata int16_t ao_error_h;
-static __pdata int16_t ao_raw_alt;
-static __pdata int16_t ao_raw_height;
-static __pdata int16_t ao_error_h_sq_avg;
-
-static void
-ao_kalman_err_height(void)
-{
- int16_t e;
- int16_t height_distrust;
-#if HAS_ACCEL
- int16_t speed_distrust;
-#endif
-
- ao_error_h = ao_raw_height - (int16_t) (ao_k_height >> 16);
-
- e = ao_error_h;
- if (e < 0)
- e = -e;
- if (e > 127)
- e = 127;
-#if HAS_ACCEL
- ao_error_h_sq_avg -= ao_error_h_sq_avg >> 2;
- ao_error_h_sq_avg += (e * e) >> 2;
-#else
- ao_error_h_sq_avg -= ao_error_h_sq_avg >> 4;
- ao_error_h_sq_avg += (e * e) >> 4;
-#endif
-
- height_distrust = ao_raw_height - AO_MAX_BARO_HEIGHT;
-#if HAS_ACCEL
- /* speed is stored * 16, but we need to ramp between 200 and 328, so
- * we want to multiply by 2. The result is a shift by 3.
- */
- speed_distrust = (ao_speed - AO_MS_TO_SPEED(AO_MAX_BARO_SPEED)) >> (4 - 1);
- if (speed_distrust <= 0)
- speed_distrust = 0;
- else if (speed_distrust > height_distrust)
- height_distrust = speed_distrust;
-#endif
- if (height_distrust <= 0)
- height_distrust = 0;
-
- if (height_distrust) {
-#ifdef AO_FLIGHT_TEST
- int old_ao_error_h = ao_error_h;
-#endif
- if (height_distrust > 0x100)
- height_distrust = 0x100;
- ao_error_h = (int16_t) (((int32_t) ao_error_h * (0x100 - height_distrust)) >> 8);
-#ifdef AO_FLIGHT_TEST
- if (ao_flight_debug) {
- printf("over height %g over speed %g distrust: %g height: error %d -> %d\n",
- (double) (ao_raw_height - AO_MAX_BARO_HEIGHT),
- (ao_speed - AO_MS_TO_SPEED(AO_MAX_BARO_SPEED)) / 16.0,
- height_distrust / 256.0,
- old_ao_error_h, ao_error_h);
- }
-#endif
- }
-}
-
-static void
-ao_kalman_correct_baro(void)
-{
- ao_kalman_err_height();
-#ifdef AO_FLIGHT_TEST
- if (ao_flight_tick - ao_flight_prev_tick > 5) {
- ao_k_height += (int32_t) AO_BARO_K0_10 * ao_error_h;
- ao_k_speed += (int32_t) AO_BARO_K1_10 * ao_error_h;
- ao_k_accel += (int32_t) AO_BARO_K2_10 * ao_error_h;
- return;
- }
-#endif
- ao_k_height += (int32_t) AO_BARO_K0_100 * ao_error_h;
- ao_k_speed += (int32_t) AO_BARO_K1_100 * ao_error_h;
- ao_k_accel += (int32_t) AO_BARO_K2_100 * ao_error_h;
-}
-
-#if HAS_ACCEL
-static __pdata int16_t ao_error_a;
-static __pdata int32_t ao_accel_scale;
-
-static void
-ao_kalman_err_accel(void)
-{
- int32_t accel;
-
- accel = (ao_ground_accel - ao_raw_accel) * ao_accel_scale;
-
- /* Can't use ao_accel here as it is the pre-prediction value still */
- ao_error_a = (accel - ao_k_accel) >> 16;
-}
-
-static void
-ao_kalman_correct_both(void)
-{
- ao_kalman_err_height();
- ao_kalman_err_accel();
-
-#ifdef AO_FLIGHT_TEST
- if (ao_flight_tick - ao_flight_prev_tick > 5) {
- if (ao_flight_debug) {
- printf ("correct speed %g + (%g * %g) + (%g * %g) = %g\n",
- ao_k_speed / (65536.0 * 16.0),
- (double) ao_error_h, AO_BOTH_K10_10 / 65536.0,
- (double) ao_error_a, AO_BOTH_K11_10 / 65536.0,
- (ao_k_speed +
- (int32_t) AO_BOTH_K10_10 * ao_error_h +
- (int32_t) AO_BOTH_K11_10 * ao_error_a) / (65536.0 * 16.0));
- }
- ao_k_height +=
- (int32_t) AO_BOTH_K00_10 * ao_error_h +
- (int32_t) AO_BOTH_K01_10 * ao_error_a;
- ao_k_speed +=
- (int32_t) AO_BOTH_K10_10 * ao_error_h +
- (int32_t) AO_BOTH_K11_10 * ao_error_a;
- ao_k_accel +=
- (int32_t) AO_BOTH_K20_10 * ao_error_h +
- (int32_t) AO_BOTH_K21_10 * ao_error_a;
- return;
- }
- if (ao_flight_debug) {
- printf ("correct speed %g + (%g * %g) + (%g * %g) = %g\n",
- ao_k_speed / (65536.0 * 16.0),
- (double) ao_error_h, AO_BOTH_K10_100 / 65536.0,
- (double) ao_error_a, AO_BOTH_K11_100 / 65536.0,
- (ao_k_speed +
- (int32_t) AO_BOTH_K10_100 * ao_error_h +
- (int32_t) AO_BOTH_K11_100 * ao_error_a) / (65536.0 * 16.0));
- }
-#endif
- ao_k_height +=
- (int32_t) AO_BOTH_K00_100 * ao_error_h +
- (int32_t) AO_BOTH_K01_100 * ao_error_a;
- ao_k_speed +=
- (int32_t) AO_BOTH_K10_100 * ao_error_h +
- (int32_t) AO_BOTH_K11_100 * ao_error_a;
- ao_k_accel +=
- (int32_t) AO_BOTH_K20_100 * ao_error_h +
- (int32_t) AO_BOTH_K21_100 * ao_error_a;
-}
-
-#ifdef FORCE_ACCEL
-static void
-ao_kalman_correct_accel(void)
-{
- ao_kalman_err_accel();
-
- if (ao_flight_tick - ao_flight_prev_tick > 5) {
- ao_k_height +=(int32_t) AO_ACCEL_K0_10 * ao_error_a;
- ao_k_speed += (int32_t) AO_ACCEL_K1_10 * ao_error_a;
- ao_k_accel += (int32_t) AO_ACCEL_K2_10 * ao_error_a;
- return;
- }
- ao_k_height += (int32_t) AO_ACCEL_K0_100 * ao_error_a;
- ao_k_speed += (int32_t) AO_ACCEL_K1_100 * ao_error_a;
- ao_k_accel += (int32_t) AO_ACCEL_K2_100 * ao_error_a;
-}
-#endif
-#endif /* HAS_ACCEL */
-
-__xdata int32_t ao_raw_pres_sum;
-
-#ifdef HAS_ACCEL
-__xdata int32_t ao_raw_accel_sum;
-#endif
-
/* Landing is detected by getting constant readings from both pressure and accelerometer
* for a fairly long time (AO_INTERVAL_TICKS)
*/
void
ao_flight(void)
{
- __pdata static uint16_t nsamples = 0;
-
- ao_flight_adc = ao_adc_head;
- ao_raw_pres = 0;
-#if HAS_ACCEL
- ao_raw_accel_prev = 0;
- ao_raw_accel = 0;
-#endif
- ao_flight_tick = 0;
+ ao_sample_init();
+ ao_flight_state = ao_flight_startup;
for (;;) {
- ao_wakeup(DATA_TO_XDATA(&ao_flight_adc));
- ao_sleep(DATA_TO_XDATA(&ao_adc_head));
- while (ao_flight_adc != ao_adc_head) {
- __xdata struct ao_adc *ao_adc;
- ao_flight_prev_tick = ao_flight_tick;
-
- /* Capture a sample */
- ao_adc = &ao_adc_ring[ao_flight_adc];
- ao_flight_tick = ao_adc->tick;
- ao_raw_pres = ao_adc->pres;
- ao_raw_alt = ao_pres_to_altitude(ao_raw_pres);
- ao_raw_height = ao_raw_alt - ao_ground_height;
-#if HAS_ACCEL
- 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
-#endif
- if (ao_flight_state > ao_flight_idle) {
- ao_kalman_predict();
-#if HAS_ACCEL
- if (ao_flight_state <= ao_flight_coast) {
-#ifdef FORCE_ACCEL
- ao_kalman_correct_accel();
-#else
- ao_kalman_correct_both();
-#endif
- } else
-#endif
- ao_kalman_correct_baro();
- ao_height = from_fix(ao_k_height);
- ao_speed = from_fix(ao_k_speed);
- ao_accel = from_fix(ao_k_accel);
- if (ao_height > ao_max_height)
- ao_max_height = ao_height;
- }
- ao_flight_adc = ao_adc_ring_next(ao_flight_adc);
- }
+ /*
+ * Process ADC samples, just looping
+ * until the sensors are calibrated.
+ */
+ if (!ao_sample())
+ continue;
switch (ao_flight_state) {
case ao_flight_startup:
- /* startup state:
- *
- * Collect 512 samples of acceleration and pressure
- * data and average them to find the resting values
- */
- if (nsamples < 512) {
-#if HAS_ACCEL
- ao_raw_accel_sum += ao_raw_accel;
-#endif
- ao_raw_pres_sum += ao_raw_pres;
- ++nsamples;
- continue;
- }
- ao_config_get();
-#if HAS_ACCEL
- ao_ground_accel = ao_raw_accel_sum >> 9;
- ao_accel_2g = ao_config.accel_minus_g - ao_config.accel_plus_g;
- ao_accel_scale = to_fix32(GRAVITY * 2 * 16) / ao_accel_2g;
-#endif
- ao_ground_pres = ao_raw_pres_sum >> 9;
- ao_ground_height = ao_pres_to_altitude(ao_ground_pres);
-
/* Check to see what mode we should go to.
* - Invalid mode if accel cal appears to be out
* - pad mode if we're upright,
)
{
ao_flight_state = ao_flight_boost;
- ao_launch_tick = ao_flight_tick;
+ ao_launch_tick = ao_sample_tick;
/* start logging data */
ao_log_start();
* (15 seconds) has past.
*/
if ((ao_accel < AO_MSS_TO_ACCEL(-2.5) && ao_height > AO_M_TO_HEIGHT(100)) ||
- (int16_t) (ao_flight_tick - ao_launch_tick) > BOOST_TICKS_MAX)
+ (int16_t) (ao_sample_tick - ao_launch_tick) > BOOST_TICKS_MAX)
{
#if HAS_ACCEL
ao_flight_state = ao_flight_fast;
*/
if (ao_speed < 0
#if !HAS_ACCEL
- && (ao_raw_alt >= AO_MAX_BARO_HEIGHT || ao_error_h_sq_avg < 100)
+ && (ao_sample_alt >= AO_MAX_BARO_HEIGHT || ao_error_h_sq_avg < 100)
#endif
)
{
*/
/* initialize interval values */
- ao_interval_end = ao_flight_tick + AO_INTERVAL_TICKS;
+ ao_interval_end = ao_sample_tick + AO_INTERVAL_TICKS;
ao_interval_min_height = ao_interval_max_height = ao_height;
if (ao_height > ao_interval_max_height)
ao_interval_max_height = ao_height;
- if ((int16_t) (ao_flight_tick - ao_interval_end) >= 0) {
+ if ((int16_t) (ao_sample_tick - ao_interval_end) >= 0) {
if (ao_height < AO_M_TO_HEIGHT(1000) &&
ao_interval_max_height - ao_interval_min_height < AO_M_TO_HEIGHT(5))
{
ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
}
ao_interval_min_height = ao_interval_max_height = ao_height;
- ao_interval_end = ao_flight_tick + AO_INTERVAL_TICKS;
+ ao_interval_end = ao_sample_tick + AO_INTERVAL_TICKS;
}
break;
case ao_flight_landed:
projects / fw / altos / blobdiff