Phase 3: MFRC522 RFID subsystem on Core 0 with UID hex conversion, enable FreeRTOS SMP

main/rfid_manager.h

@@ -0,0 +1,49 @@
+/*
+ * MTG RFID Companion - MFRC522 RFID manager (Core 0)
+ *
+ * Phase 3: Initializes the MFRC522 as a device on the shared SPI2_HOST bus,
+ * registers an ESP event loop listener for card state changes, converts UIDs
+ * to uppercase hex strings, and pins the polling task to Core 0.
+ */
+
+#pragma once
+
+#include "esp_err.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define RFID_UID_STR_MAX_LEN (24) /* 10 bytes x 2 hex chars */
+
+/**
+ * @brief Initialize the MFRC522 driver and register event listeners.
+ * @return ESP_OK on success.
+ */
+esp_err_t rfid_manager_init(void);
+
+/**
+ * @brief Start polling for cards and pin the polling task to Core 0.
+ * @return ESP_OK on success.
+ */
+esp_err_t rfid_manager_start(void);
+
+/**
+ * @brief Return the most recently scanned UID (uppercase hex, no separators).
+ *        8 chars for 4-byte UIDs, 14 chars for 7-byte UIDs.
+ */
+const char *rfid_manager_last_uid(void);
+
+/**
+ * @brief True once a new card has been scanned since the last poll().
+ */
+bool rfid_manager_has_pending_card(void);
+
+/**
+ * @brief Clear the pending-card flag (call after consuming the UID).
+ */
+void rfid_manager_consume_card(void);
+
+#ifdef __cplusplus
+}
+#endif