Initial commit: project docs and ignore rules

nfc_protocol.h

@@ -0,0 +1,67 @@
+#ifndef NFC_PROTOCOL_H
+#define NFC_PROTOCOL_H
+
+#include <Arduino.h>
+
+// Communication protocol definitions
+#define MAX_NFC_DATA_SIZE 256
+#define ESPNOW_CHANNEL 1
+#define PAIRING_TIMEOUT_MS 30000
+#define HEARTBEAT_INTERVAL_MS 1000
+#define MAX_RETRY_ATTEMPTS 3
+
+// Message types
+enum MessageType {
+    MSG_PAIRING_REQUEST = 0x01,
+    MSG_PAIRING_RESPONSE = 0x02,
+    MSG_NFC_DATA = 0x03,
+    MSG_HEARTBEAT = 0x04,
+    MSG_ERROR = 0x05,
+    MSG_ACK = 0x06
+};
+
+// NFC data structure
+struct NFCData {
+    uint8_t uid[10];          // NFC UID (max 10 bytes)
+    uint8_t uid_length;       // Actual UID length
+    uint8_t sak;              // Select Acknowledge
+    uint8_t atqa[2];          // Answer to Request Type A
+    uint8_t raw_data[MAX_NFC_DATA_SIZE];  // Raw NFC data
+    uint16_t data_length;     // Actual data length
+    uint32_t timestamp;       // Capture timestamp
+    uint8_t tag_type;         // NFC tag type
+};
+
+// Communication message structure
+struct CommMessage {
+    uint8_t type;             // Message type
+    uint8_t sequence;         // Sequence number
+    uint16_t payload_size;    // Payload size
+    union {
+        NFCData nfc_data;
+        uint8_t raw_payload[sizeof(NFCData)];
+    };
+    uint16_t checksum;        // Message integrity check
+};
+
+// Device roles
+enum DeviceRole {
+    ROLE_LISTENER = 1,
+    ROLE_EMULATOR = 2
+};
+
+// Status codes
+enum StatusCode {
+    STATUS_OK = 0,
+    STATUS_ERROR = 1,
+    STATUS_TIMEOUT = 2,
+    STATUS_INVALID_DATA = 3,
+    STATUS_NOT_PAIRED = 4
+};
+
+// Function prototypes
+uint16_t calculateChecksum(const uint8_t* data, size_t length);
+bool validateMessage(const CommMessage* msg);
+void printNFCData(const NFCData* data);
+
+#endif // NFC_PROTOCOL_H