/** Do a blocking acquisition search.
* Perform an acquisition for one PRN over a defined code and doppler range.
* Returns the code phase and carrier frequency of the largest peak in the
* search space together with the "SNR" value for that peak defined as
* (peak_magnitude - mean) / std_deviation.
*
* \param prn PRN number - 1 (0..31) to attempt to acquire
* (nap_acq_code_wr_blocking must be called prior).
* \param cp_min Lower bound for code phase search range in chips.
* \param cp_max Upper bound for code phase search range in chips.
* \param cf_min Lower bound for carrier freq. search range in Hz.
* \param cf_max Upper bound for carrier freq. search range in Hz.
* \param cp Pointer to a float where the peak's code phase value will be
* stored in chips.
* \param cf Pointer to a float where the peak's carrier frequency will be
* stored in Hz.
* \param snr Pointer to a float where the "SNR" of the peak will be stored.
*/
void do_acq(u8 prn, float cp_min, float cp_max, float cf_min, float cf_max, float cf_bin_width, float* cp, float* cf, float* snr)
{
acq_start(prn, cp_min, cp_max, cf_min, cf_max, cf_bin_width);
while(acq_state.state == ACQ_RUNNING) {
wait_for_nap_exti();
acq_service_irq();
}
wait_for_nap_exti();
acq_service_irq();
acq_get_results(cp, cf, snr);
}
static void handle_nap_exti(void)
{
u32 irq = nap_irq_rd_blocking();
if (irq & NAP_IRQ_ACQ_DONE)
acq_service_irq();
if (irq & NAP_IRQ_ACQ_LOAD_DONE)
acq_service_load_done();
if (irq & NAP_IRQ_TIMING_STROBE) {
chBSemReset(&timing_strobe_sem, TRUE);
}
if (irq & NAP_IRQ_EXT_EVENT)
ext_event_service();
/* Mask off everything but tracking irqs. */
irq &= NAP_IRQ_TRACK_MASK;
tracking_channels_update(irq);
u32 err = nap_error_rd_blocking();
if (err) {
log_error("SwiftNAP Error: 0x%08X", (unsigned int)err);
tracking_channels_missed_update_error(err);
}
watchdog_notify(WD_NOTIFY_NAP_ISR);
nap_exti_count++;
}