77 lines
2.4 KiB
C
77 lines
2.4 KiB
C
/**
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* @file protocol.h
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* @brief AliceRC communication protocol definitions
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*
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* Matches the AliceRX_STC receiver protocol:
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* - NRF24L01 32-byte payload
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* - Frame ID 0xA0 for channel data
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* - ACK payload 0xB0 for telemetry
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* - 16 SBUS channels packed as 11-bit little-endian bitstream
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*/
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#pragma once
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#include <stdint.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* Protocol constants */
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#define FRAME_ID_CHANNELS 0xA0
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#define FRAME_ID_TELEMETRY 0xB0
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#define RF_PAYLOAD_SIZE 32
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#define RF_ADDR_SIZE 5
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#define SBUS_CHANNEL_COUNT 16
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#define SBUS_CHANNEL_BITS 11
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/* NRF24L01 TX payload (32 bytes) */
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typedef struct __attribute__((packed)) {
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uint8_t frame_id; /* 0xA0 = FRAME_ID_CHANNELS */
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uint8_t seq; /* Sequence number, wraps around */
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uint8_t model_id; /* Currently selected model ID */
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uint8_t flags; /* Flags (reserved for future use) */
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uint8_t sbus_data[22]; /* 16 channels × 11 bit = 176 bit, little-endian */
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uint8_t reserved[6]; /* Reserved for future use */
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} rf_tx_payload_t;
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/* NRF24L01 ACK payload from receiver (32 bytes) */
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typedef struct __attribute__((packed)) {
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uint8_t frame_id; /* 0xB0 = FRAME_ID_TELEMETRY */
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uint8_t seq; /* Sequence number */
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uint16_t battery_mv; /* Battery voltage in mV (big-endian) */
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uint8_t reserved[28]; /* Reserved for future use */
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} rf_rx_telemetry_t;
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/* SBUS channel value range */
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#define SBUS_MIN 200
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#define SBUS_CENTER 1024
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#define SBUS_MAX 1844
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/* Function declarations */
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/* Initialize protocol module */
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void protocol_init(void);
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/* Pack SBUS channels into 22-byte bitstream */
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void protocol_pack_sbus(const uint16_t *channels, uint8_t *sbus_data);
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/* Unpack SBUS channels from 22-byte bitstream */
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void protocol_unpack_sbus(const uint8_t *sbus_data, uint16_t *channels);
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/* Build TX payload from ADC channel values */
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void protocol_build_tx_payload(rf_tx_payload_t *payload,
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const uint16_t *adc_channels,
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uint8_t model_id,
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uint8_t seq);
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/* Parse telemetry data from receiver */
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void protocol_parse_telemetry(const rf_rx_telemetry_t *telemetry,
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uint16_t *battery_mv);
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/* Map ADC value (0-4095) to SBUS range (200-1844) */
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uint16_t protocol_map_to_sbus(uint16_t adc_value);
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#ifdef __cplusplus
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}
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#endif
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