Initial commit - sync AliceRC to Gitea

AliceRC_ESP32/components/protocol/CMakeLists.txt

@@ -0,0 +1,5 @@
+idf_component_register(
+    SRCS "protocol.c"
+    INCLUDE_DIRS "."
+    REQUIRES nrf24l01
+)

AliceRC_ESP32/components/protocol/protocol.c

@@ -0,0 +1,89 @@
+/**
+ * @file protocol.c
+ * @brief AliceRC communication protocol implementation
+ */
+#include <string.h>
+#include "protocol.h"
+
+void protocol_init(void)
+{
+    /* Nothing to initialize for now */
+}
+
+void protocol_pack_sbus(const uint16_t *channels, uint8_t *sbus_data)
+{
+    memset(sbus_data, 0, 22);
+    
+    /* Pack 16 × 11-bit channels into 22 bytes, little-endian bitstream */
+    for (int i = 0; i < SBUS_CHANNEL_COUNT; i++) {
+        uint16_t ch = channels[i] & 0x07FF;  /* Mask to 11 bits */
+        int byte_idx = (i * SBUS_CHANNEL_BITS) / 8;
+        int bit_off = (i * SBUS_CHANNEL_BITS) % 8;
+        
+        sbus_data[byte_idx] |= (ch << bit_off) & 0xFF;
+        sbus_data[byte_idx + 1] |= (ch >> (8 - bit_off)) & 0xFF;
+        if (bit_off > 5) {
+            /* 11-bit crosses 3-byte boundary when bit_off >= 6 */
+            sbus_data[byte_idx + 2] |= (ch >> (16 - bit_off)) & 0xFF;
+        }
+    }
+}
+
+void protocol_unpack_sbus(const uint8_t *sbus_data, uint16_t *channels)
+{
+    for (int i = 0; i < SBUS_CHANNEL_COUNT; i++) {
+        int byte_idx = (i * SBUS_CHANNEL_BITS) / 8;
+        int bit_off = (i * SBUS_CHANNEL_BITS) % 8;
+        
+        uint16_t ch = sbus_data[byte_idx] >> bit_off;
+        ch |= (uint16_t)(sbus_data[byte_idx + 1]) << (8 - bit_off);
+        if (bit_off > 5) {
+            ch |= (uint16_t)(sbus_data[byte_idx + 2]) << (16 - bit_off);
+        }
+        
+        channels[i] = ch & 0x07FF;
+    }
+}
+
+void protocol_build_tx_payload(rf_tx_payload_t *payload,
+                               const uint16_t *adc_channels,
+                               uint8_t model_id,
+                               uint8_t seq)
+{
+    uint16_t sbus_channels[SBUS_CHANNEL_COUNT];
+    
+    /* Convert 8 ADC channels to SBUS range, center the rest */
+    for (int i = 0; i < 8; i++) {
+        sbus_channels[i] = protocol_map_to_sbus(adc_channels[i]);
+    }
+    for (int i = 8; i < SBUS_CHANNEL_COUNT; i++) {
+        sbus_channels[i] = SBUS_CENTER;
+    }
+    
+    /* Build payload */
+    memset(payload, 0, sizeof(rf_tx_payload_t));
+    payload->frame_id = FRAME_ID_CHANNELS;
+    payload->seq = seq;
+    payload->model_id = model_id;
+    payload->flags = 0;
+    
+    protocol_pack_sbus(sbus_channels, payload->sbus_data);
+}
+
+void protocol_parse_telemetry(const rf_rx_telemetry_t *telemetry,
+                              uint16_t *battery_mv)
+{
+    if (telemetry->frame_id == FRAME_ID_TELEMETRY) {
+        /* Battery voltage is big-endian */
+        *battery_mv = (telemetry->battery_mv >> 8) | 
+                       (telemetry->battery_mv << 8);
+    }
+}
+
+uint16_t protocol_map_to_sbus(uint16_t adc_value)
+{
+    /* Map 12-bit ADC (0-4095) to SBUS range (200-1844) */
+    uint32_t result = SBUS_MIN + ((uint32_t)adc_value * (SBUS_MAX - SBUS_MIN) / 4095);
+    if (result > SBUS_MAX) result = SBUS_MAX;
+    return (uint16_t)result;
+}

AliceRC_ESP32/components/protocol/protocol.h

@@ -0,0 +1,76 @@
+/**
+ * @file protocol.h
+ * @brief AliceRC communication protocol definitions
+ * 
+ * Matches the AliceRX_STC receiver protocol:
+ * - NRF24L01 32-byte payload
+ * - Frame ID 0xA0 for channel data
+ * - ACK payload 0xB0 for telemetry
+ * - 16 SBUS channels packed as 11-bit little-endian bitstream
+ */
+#pragma once
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Protocol constants */
+#define FRAME_ID_CHANNELS      0xA0
+#define FRAME_ID_TELEMETRY     0xB0
+#define RF_PAYLOAD_SIZE        32
+#define RF_ADDR_SIZE           5
+#define SBUS_CHANNEL_COUNT     16
+#define SBUS_CHANNEL_BITS      11
+
+/* NRF24L01 TX payload (32 bytes) */
+typedef struct __attribute__((packed)) {
+    uint8_t frame_id;       /* 0xA0 = FRAME_ID_CHANNELS */
+    uint8_t seq;            /* Sequence number, wraps around */
+    uint8_t model_id;       /* Currently selected model ID */
+    uint8_t flags;          /* Flags (reserved for future use) */
+    uint8_t sbus_data[22];  /* 16 channels × 11 bit = 176 bit, little-endian */
+    uint8_t reserved[6];    /* Reserved for future use */
+} rf_tx_payload_t;
+
+/* NRF24L01 ACK payload from receiver (32 bytes) */
+typedef struct __attribute__((packed)) {
+    uint8_t frame_id;       /* 0xB0 = FRAME_ID_TELEMETRY */
+    uint8_t seq;            /* Sequence number */
+    uint16_t battery_mv;    /* Battery voltage in mV (big-endian) */
+    uint8_t reserved[28];   /* Reserved for future use */
+} rf_rx_telemetry_t;
+
+/* SBUS channel value range */
+#define SBUS_MIN        200
+#define SBUS_CENTER     1024
+#define SBUS_MAX        1844
+
+/* Function declarations */
+
+/* Initialize protocol module */
+void protocol_init(void);
+
+/* Pack SBUS channels into 22-byte bitstream */
+void protocol_pack_sbus(const uint16_t *channels, uint8_t *sbus_data);
+
+/* Unpack SBUS channels from 22-byte bitstream */
+void protocol_unpack_sbus(const uint8_t *sbus_data, uint16_t *channels);
+
+/* Build TX payload from ADC channel values */
+void protocol_build_tx_payload(rf_tx_payload_t *payload, 
+                               const uint16_t *adc_channels, 
+                               uint8_t model_id,
+                               uint8_t seq);
+
+/* Parse telemetry data from receiver */
+void protocol_parse_telemetry(const rf_rx_telemetry_t *telemetry,
+                              uint16_t *battery_mv);
+
+/* Map ADC value (0-4095) to SBUS range (200-1844) */
+uint16_t protocol_map_to_sbus(uint16_t adc_value);
+
+#ifdef __cplusplus
+}
+#endif