add the command 0x11 - get slave info

test/serial/mb_serial_master/main/master.c

@@ -305,6 +305,26 @@ static void master_operation_func(void *arg)
 
     ESP_LOGI(TAG, "Start modbus test...");
 
+    // Command - 17 (0x11) Report Slave ID (Serial Line only)
+    // The command contains vendor specific data and should be interpreted accordingly.
+    // This version of command handler needs to define the maximum number
+    // of registers that can be returned from concrete slave (buffer size).
+    // The returned slave info data will be stored into the `info_buf`.
+    // Request fields: slave_addr - the UID of slave, reg_start - not used, 
+    // reg_size = max size of buffer (registers).
+    mb_param_request_t req = {.slave_addr = 1, .command = 0x11, 
+                                .reg_start = 0, .reg_size = (CONFIG_FMB_CONTROLLER_SLAVE_ID_MAX_SIZE >> 1)};
+
+    uint8_t info_buf[CONFIG_FMB_CONTROLLER_SLAVE_ID_MAX_SIZE] = {0};
+
+    // This is the way to retrieve slave ID information from slave (vendor specific command = 0x11).
+    err = mbc_master_send_request(&req, &info_buf[0]);
+    if (err != ESP_OK) {
+        ESP_LOGE("SLAVE_INFO", "Read slave info fail.");
+    } else {
+        ESP_LOG_BUFFER_HEX_LEVEL("SLAVE_INFO", (void*)info_buf, sizeof(info_buf), ESP_LOG_WARN);
+    }
+
     for(uint16_t retry = 0; retry <= MASTER_MAX_RETRY && (!alarm_state); retry++) {
         // Read all found characteristics from slave(s)
         for (uint16_t cid = 0; (err != ESP_ERR_NOT_FOUND) && cid < MASTER_MAX_CIDS; cid++) {

test/serial/mb_serial_slave/main/slave.c

@@ -126,6 +126,10 @@ static void setup_reg_data(void)
     input_reg_params.input_data7 = 4.78;
 }
 
+// This is the way to expose the funcion to set slave ID .
+// The related function is vendor specific and stack by default hides this functionality from user.
+extern int eMBSetSlaveID(uint8_t slave_id, bool is_running, uint8_t const *pdata, uint16_t data_len);
+
 // 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
@@ -226,6 +230,15 @@ void app_main(void)
     ESP_LOGI(TAG, "Modbus slave stack initialized.");
     ESP_LOGI(TAG, "Start modbus test...");
 
+    uint8_t ext_data[] = {0x11, 0x22, 0x33, 0x44, 0x55};
+    // This is the way to set Slave ID fields to retrieve it by master using report slave ID command.
+    int err = eMBSetSlaveID(comm_info.slave_addr, true, (uint8_t *)&ext_data, sizeof(ext_data));
+    if (!err) {
+        ESP_LOG_BUFFER_HEX_LEVEL("SET_SLAVE_ID", (void*)ext_data, sizeof(ext_data), ESP_LOG_WARN);
+    } else {
+        ESP_LOGE("SET_SLAVE_ID", "Set slave ID fail, err=%d.", err);
+    }
+
     // 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;) {