108 lines
2.9 KiB
C++
108 lines
2.9 KiB
C++
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#include "decoder_ioprox.h"
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#include <furi_hal.h>
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#include <cli/cli.h>
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#include <utility>
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constexpr uint32_t clocks_in_us = 64;
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constexpr uint32_t jitter_time_us = 20;
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constexpr uint32_t min_time_us = 64;
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constexpr uint32_t max_time_us = 80;
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constexpr uint32_t baud_time_us = 500;
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constexpr uint32_t min_time = (min_time_us - jitter_time_us) * clocks_in_us;
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constexpr uint32_t mid_time = ((max_time_us - min_time_us) / 2 + min_time_us) * clocks_in_us;
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constexpr uint32_t max_time = (max_time_us + jitter_time_us) * clocks_in_us;
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constexpr uint32_t baud_time = baud_time_us * clocks_in_us;
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bool DecoderIoProx::read(uint8_t* data, uint8_t data_size) {
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bool result = false;
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furi_assert(data_size >= 4);
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if(ready) {
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result = true;
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ioprox.decode(raw_data, sizeof(raw_data), data, data_size);
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ready = false;
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}
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return result;
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}
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void DecoderIoProx::process_front(bool is_rising_edge, uint32_t time) {
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if(ready) {
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return;
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}
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// Always track the time that's gone by.
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current_period_duration += time;
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demodulation_sample_duration += time;
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// If a baud time has elapsed, we're at a sample point.
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if(demodulation_sample_duration >= baud_time) {
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// Start a new baud period...
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demodulation_sample_duration = 0;
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demodulated_value_invalid = false;
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// ... and if we didn't have any baud errors, capture a sample.
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if(!demodulated_value_invalid) {
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store_data(current_demodulated_value);
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}
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}
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//
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// FSK demodulator.
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//
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// If this isn't a rising edge, this isn't a pulse of interest.
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// We're done.
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if(!is_rising_edge) {
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return;
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}
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bool is_valid_low = (current_period_duration > min_time) &&
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(current_period_duration <= mid_time);
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bool is_valid_high = (current_period_duration > mid_time) &&
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(current_period_duration < max_time);
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// If this is between the minimum and our threshold, this is a logical 0.
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if(is_valid_low) {
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current_demodulated_value = false;
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}
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// Otherwise, if between our threshold and the max time, it's a logical 1.
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else if(is_valid_high) {
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current_demodulated_value = true;
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}
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// Otherwise, invalidate this sample.
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else {
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demodulated_value_invalid = true;
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}
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// We're starting a new period; track that.
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current_period_duration = 0;
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}
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DecoderIoProx::DecoderIoProx() {
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reset_state();
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}
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void DecoderIoProx::store_data(bool data) {
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for(int i = 0; i < 7; ++i) {
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raw_data[i] = (raw_data[i] << 1) | ((raw_data[i + 1] >> 7) & 1);
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}
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raw_data[7] = (raw_data[7] << 1) | data;
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if(ioprox.can_be_decoded(raw_data, sizeof(raw_data))) {
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ready = true;
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}
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}
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void DecoderIoProx::reset_state() {
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current_demodulated_value = false;
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demodulated_value_invalid = false;
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current_period_duration = 0;
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demodulation_sample_duration = 0;
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ready = false;
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}
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