chore: housekeeping

include/modbus.h

@@ -0,0 +1,56 @@
+#ifndef MODBUS_H
+#define MODBUS_H
+
+#include <MQTT/MQTTClient.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+#include "config.h"
+
+// Function codes
+#define MODBUS_FC_READ_HOLDING_REGISTERS 0x03
+#define MODBUS_FC_WRITE_SINGLE_REGISTER 0x06
+#define MODBUS_FC_WRITE_MULTIPLE_REGISTERS 0x10
+
+// Modbus protocol exception codes
+#define MODBUS_ERROR_NONE 0x00
+#define MODBUS_ERROR_ILLEGAL_FUNCTION 0x01
+#define MODBUS_ERROR_ILLEGAL_ADDRESS 0x02
+#define MODBUS_ERROR_ILLEGAL_VALUE 0x03
+#define MODBUS_ERROR_DEVICE_FAILURE 0x04
+#define MODBUS_ERROR_ACKNOWLEDGE 0x05
+#define MODBUS_ERROR_DEVICE_BUSY 0x06
+#define MODBUS_ERROR_MEMORY_PARITY 0x08
+#define MODBUS_ERROR_TIMEOUT 0x0B  // No response received
+#define MODBUS_ERROR_CRC 0x0C      // CRC check failed
+
+// Frame length
+#define MB_MIN_LEN 4
+#define MB_CRC_LEN 2
+#define MB_WREG_LEN 8
+#define MB_MAX_BUFFER 32
+
+// States for the Modbus protocol state machine
+typedef enum {
+  MODBUS_IDLE,              // Ready to send new request
+  MODBUS_WAITING_RESPONSE,  // Request sent, waiting for slave response
+  MODBUS_PROCESS_RESPONSE   // Response received, processing data
+} modbus_state_t;
+
+// Callback function type for handling received Modbus register values
+typedef void (*modbus_value_cb)(uint8_t device_idx, const char* property,
+                                uint16_t value);
+
+// Initialize the Modbus protocol handler with callback for received values
+void modbus_handler_init(modbus_value_cb value_callback);
+void modbus_handler_process(void);
+// Send a Modbus read or write request to a slave device
+// Returns true if request was queued successfully
+bool modbus_handler_send_request(uint8_t device_idx, const char* property,
+                                 bool is_write, uint16_t value);
+// Publish a Modbus register value to MQTT broker
+// Formats topic as device_name/property
+void modbus_publish_value(MQTTClient* client, const char* device_name,
+                          const char* property, uint16_t value);
+
+#endif  // MODBUS_H