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/*
* SPDX-FileCopyrightText: 2016-2023 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
// FreeModbus Slave Example ESP32
#include <stdio.h>
#include <stdint.h>
#include "esp_err.h"
#include "mbcontroller.h" // for mbcontroller defines and api
#include "modbus_params.h" // for modbus parameters structures
#include "esp_log.h" // for log_write
#include "sdkconfig.h"
#define MB_PORT_NUM (CONFIG_MB_UART_PORT_NUM) // Number of UART port used for Modbus connection
#define MB_SLAVE_ADDR (CONFIG_MB_SLAVE_ADDR) // The address of device in Modbus network
#define MB_DEV_SPEED (CONFIG_MB_UART_BAUD_RATE) // The communication speed of the UART
// Note: Some pins on target chip cannot be assigned for UART communication.
// Please refer to documentation for selected board and target to configure pins using Kconfig.
// Defines below are used to define register start address for each type of Modbus registers
#define HOLD_OFFSET(field) ((uint16_t)(offsetof(holding_reg_params_t, field) >> 1))
#define INPUT_OFFSET(field) ((uint16_t)(offsetof(input_reg_params_t, field) >> 1))
#define MB_REG_DISCRETE_INPUT_START (0x0000)
#define MB_REG_COILS_START (0x0000)
#define MB_REG_INPUT_START_AREA0 (INPUT_OFFSET(input_data0)) // register offset input area 0
#define MB_REG_INPUT_START_AREA1 (INPUT_OFFSET(input_data4)) // register offset input area 1
#define MB_REG_HOLDING_START_AREA0 (HOLD_OFFSET(holding_data0))
#define MB_REG_HOLDING_START_AREA1 (HOLD_OFFSET(holding_data4))
#define MB_PAR_INFO_GET_TOUT (10) // Timeout for get parameter info
#define MB_CHAN_DATA_MAX_VAL (6)
#define MB_CHAN_DATA_OFFSET (0.2f)
#define MB_READ_MASK (MB_EVENT_INPUT_REG_RD \
| MB_EVENT_HOLDING_REG_RD \
| MB_EVENT_DISCRETE_RD \
| MB_EVENT_COILS_RD)
#define MB_WRITE_MASK (MB_EVENT_HOLDING_REG_WR \
| MB_EVENT_COILS_WR)
#define MB_READ_WRITE_MASK (MB_READ_MASK | MB_WRITE_MASK)
static const char *TAG = "SLAVE_TEST";
static portMUX_TYPE param_lock = portMUX_INITIALIZER_UNLOCKED;
// Set register values into known state
static void setup_reg_data(void)
{
// Define initial state of parameters
discrete_reg_params.discrete_input0 = 1;
discrete_reg_params.discrete_input1 = 0;
discrete_reg_params.discrete_input2 = 1;
discrete_reg_params.discrete_input3 = 0;
discrete_reg_params.discrete_input4 = 1;
discrete_reg_params.discrete_input5 = 0;
discrete_reg_params.discrete_input6 = 1;
discrete_reg_params.discrete_input7 = 0;
holding_reg_params.holding_data0 = 1.34;
holding_reg_params.holding_data1 = 2.56;
holding_reg_params.holding_data2 = 3.78;
holding_reg_params.holding_data3 = 4.90;
holding_reg_params.holding_data4 = 5.67;
holding_reg_params.holding_data5 = 6.78;
holding_reg_params.holding_data6 = 7.79;
holding_reg_params.holding_data7 = 8.80;
coil_reg_params.coils_port0 = 0x55;
coil_reg_params.coils_port1 = 0xAA;
input_reg_params.input_data0 = 1.12;
input_reg_params.input_data1 = 2.34;
input_reg_params.input_data2 = 3.56;
input_reg_params.input_data3 = 4.78;
input_reg_params.input_data4 = 1.12;
input_reg_params.input_data5 = 2.34;
input_reg_params.input_data6 = 3.56;
input_reg_params.input_data7 = 4.78;
}
// An example application of Modbus slave. It is based on freemodbus stack.
// See deviceparams.h file for more information about assigned Modbus parameters.
// These parameters can be accessed from main application and also can be changed
// by external Modbus master host.
void app_main(void)
{
mb_param_info_t reg_info; // keeps the Modbus registers access information
mb_communication_info_t comm_info; // Modbus communication parameters
mb_register_area_descriptor_t reg_area; // Modbus register area descriptor structure
// Set UART log level
esp_log_level_set(TAG, ESP_LOG_INFO);
void* mbc_slave_handler = NULL;
ESP_ERROR_CHECK(mbc_slave_init(MB_PORT_SERIAL_SLAVE, &mbc_slave_handler)); // Initialization of Modbus controller
// Setup communication mode and start stack
#if CONFIG_MB_COMM_MODE_ASCII
comm_info.mode = MB_MODE_ASCII;
#elif CONFIG_MB_COMM_MODE_RTU
comm_info.mode = MB_MODE_RTU;
#endif
comm_info.slave_addr = MB_SLAVE_ADDR;
comm_info.port = MB_PORT_NUM;
comm_info.baudrate = MB_DEV_SPEED;
comm_info.parity = MB_PARITY_NONE;
ESP_ERROR_CHECK(mbc_slave_setup((void*)&comm_info));
// The code below initializes Modbus register area descriptors
// for Modbus Holding Registers, Input Registers, Coils and Discrete Inputs
// Initialization should be done for each supported Modbus register area according to register map.
// When external master trying to access the register in the area that is not initialized
// by mbc_slave_set_descriptor() API call then Modbus stack
// will send exception response for this register area.
reg_area.type = MB_PARAM_HOLDING; // Set type of register area
reg_area.start_offset = MB_REG_HOLDING_START_AREA0; // Offset of register area in Modbus protocol
reg_area.address = (void*)&holding_reg_params.holding_data0; // Set pointer to storage instance
// Set the size of register storage instance = 150 holding registers
reg_area.size = (size_t)(HOLD_OFFSET(holding_data4) - HOLD_OFFSET(test_regs));
ESP_ERROR_CHECK(mbc_slave_set_descriptor(reg_area));
reg_area.type = MB_PARAM_HOLDING; // Set type of register area
reg_area.start_offset = MB_REG_HOLDING_START_AREA1; // Offset of register area in Modbus protocol
reg_area.address = (void*)&holding_reg_params.holding_data4; // Set pointer to storage instance
reg_area.size = sizeof(float) << 2; // Set the size of register storage instance
ESP_ERROR_CHECK(mbc_slave_set_descriptor(reg_area));
// Initialization of Input Registers area
reg_area.type = MB_PARAM_INPUT;
reg_area.start_offset = MB_REG_INPUT_START_AREA0;
reg_area.address = (void*)&input_reg_params.input_data0;
reg_area.size = sizeof(float) << 2;
ESP_ERROR_CHECK(mbc_slave_set_descriptor(reg_area));
reg_area.type = MB_PARAM_INPUT;
reg_area.start_offset = MB_REG_INPUT_START_AREA1;
reg_area.address = (void*)&input_reg_params.input_data4;
reg_area.size = sizeof(float) << 2;
ESP_ERROR_CHECK(mbc_slave_set_descriptor(reg_area));
// Initialization of Coils register area
reg_area.type = MB_PARAM_COIL;
reg_area.start_offset = MB_REG_COILS_START;
reg_area.address = (void*)&coil_reg_params;
reg_area.size = sizeof(coil_reg_params);
ESP_ERROR_CHECK(mbc_slave_set_descriptor(reg_area));
// Initialization of Discrete Inputs register area
reg_area.type = MB_PARAM_DISCRETE;
reg_area.start_offset = MB_REG_DISCRETE_INPUT_START;
reg_area.address = (void*)&discrete_reg_params;
reg_area.size = sizeof(discrete_reg_params);
ESP_ERROR_CHECK(mbc_slave_set_descriptor(reg_area));
setup_reg_data(); // Set values into known state
// Starts of modbus controller and stack
ESP_ERROR_CHECK(mbc_slave_start());
// Set UART pin numbers
ESP_ERROR_CHECK(uart_set_pin(MB_PORT_NUM, CONFIG_MB_UART_TXD,
CONFIG_MB_UART_RXD, CONFIG_MB_UART_RTS,
UART_PIN_NO_CHANGE));
// Set UART driver mode to Half Duplex
ESP_ERROR_CHECK(uart_set_mode(MB_PORT_NUM, UART_MODE_RS485_HALF_DUPLEX));
ESP_LOGI(TAG, "Modbus slave stack initialized.");
ESP_LOGI(TAG, "Start modbus test...");
// The cycle below will be terminated when parameter holdingRegParams.dataChan0
// incremented each access cycle reaches the CHAN_DATA_MAX_VAL value.
for(;holding_reg_params.holding_data0 < MB_CHAN_DATA_MAX_VAL;) {
// Check for read/write events of Modbus master for certain events
(void)mbc_slave_check_event(MB_READ_WRITE_MASK);
ESP_ERROR_CHECK_WITHOUT_ABORT(mbc_slave_get_param_info(®_info, MB_PAR_INFO_GET_TOUT));
const char* rw_str = (reg_info.type & MB_READ_MASK) ? "READ" : "WRITE";
// Filter events and process them accordingly
if(reg_info.type & (MB_EVENT_HOLDING_REG_WR | MB_EVENT_HOLDING_REG_RD)) {
// Get parameter information from parameter queue
ESP_LOGI(TAG, "HOLDING %s (%" PRIu32 " us), ADDR:%u, TYPE:%u, INST_ADDR:0x%" PRIx32 ", SIZE:%u",
rw_str,
reg_info.time_stamp,
(unsigned)reg_info.mb_offset,
(unsigned)reg_info.type,
(uint32_t)reg_info.address,
(unsigned)reg_info.size);
if (reg_info.address == (uint8_t*)&holding_reg_params.holding_data0)
{
portENTER_CRITICAL(¶m_lock);
holding_reg_params.holding_data0 += MB_CHAN_DATA_OFFSET;
if (holding_reg_params.holding_data0 >= (MB_CHAN_DATA_MAX_VAL - MB_CHAN_DATA_OFFSET)) {
coil_reg_params.coils_port1 = 0xFF;
}
portEXIT_CRITICAL(¶m_lock);
}
} else if (reg_info.type & MB_EVENT_INPUT_REG_RD) {
ESP_LOGI(TAG, "INPUT READ (%" PRIu32 " us), ADDR:%u, TYPE:%u, INST_ADDR:0x%" PRIx32 ", SIZE:%u",
reg_info.time_stamp,
(unsigned)reg_info.mb_offset,
(unsigned)reg_info.type,
(uint32_t)reg_info.address,
(unsigned)reg_info.size);
} else if (reg_info.type & MB_EVENT_DISCRETE_RD) {
ESP_LOGI(TAG, "DISCRETE READ (%" PRIu32 " us): ADDR:%u, TYPE:%u, INST_ADDR:0x%" PRIx32 ", SIZE:%u",
reg_info.time_stamp,
(unsigned)reg_info.mb_offset,
(unsigned)reg_info.type,
(uint32_t)reg_info.address,
(unsigned)reg_info.size);
} else if (reg_info.type & (MB_EVENT_COILS_RD | MB_EVENT_COILS_WR)) {
ESP_LOGI(TAG, "COILS %s (%" PRIu32 " us), ADDR:%u, TYPE:%u, INST_ADDR:0x%" PRIx32 ", SIZE:%u",
rw_str,
reg_info.time_stamp,
(unsigned)reg_info.mb_offset,
(unsigned)reg_info.type,
(uint32_t)reg_info.address,
(unsigned)reg_info.size);
if (coil_reg_params.coils_port1 == 0xFF) break;
}
}
// Destroy of Modbus controller on alarm
ESP_LOGI(TAG,"Modbus controller destroyed.");
vTaskDelay(100);
ESP_ERROR_CHECK(mbc_slave_destroy());
}
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