Espressif ESP32-S2 User Manual

Chapter 2. API Reference
MB_PARAM_HOLDING = 0x00
Modbus Holding register.
MB_PARAM_INPUT
Modbus Input register.
MB_PARAM_COIL
Modbus Coils.
MB_PARAM_DISCRETE
Modbus Discrete bits.
MB_PARAM_COUNT
MB_PARAM_UNKNOWN = 0xFF
enum mb_mode_type_t
Modbus serial transmission modes (RTU/ASCII).
Values:
MB_MODE_RTU
RTU transmission mode.
MB_MODE_ASCII
ASCII transmission mode.
MB_MODE_TCP
TCP communication mode.
MB_MODE_UDP
UDP communication mode.
enum mb_tcp_addr_type_t
Modbus TCP type of address.
Values:
MB_IPV4 = 0
TCP IPV4 addressing
MB_IPV6 = 1
TCP IPV6 addressing
Header File
• components/freemodbus/common/include/esp_modbus_master.h
Functions
esp_err_t mbc_master_init_tcp(void **handler)
Initialize Modbus controller and stack for TCP port.
Return
• ESP_OK Success
• ESP_ERR_NO_MEM Parameter error
• ESP_ERR_NOT_SUPPORTED Port type not supported
• ESP_ERR_INVALID_STATE Initialization failure
Parameters
• [out] handler: handler(pointer) to master data structure
esp_err_t mbc_master_init(mb_port_type_t port_type, void **handler)
Initialize Modbus Master controller and stack for Serial port.
Return
• ESP_OK Success
• ESP_ERR_NO_MEM Parameter error
• ESP_ERR_NOT_SUPPORTED Port type not supported
Espressif Systems 635
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Release v4.4

Espressif ESP32-S2 Specifications

General

Brand	Espressif
Model	ESP32-S2
Category	Single board computers
Language	English