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--- en:iot-open:practical:hardware:sut:stm32:iot_at [2024/04/25 10:20] – [Steps] ktokarz
+++ en:iot-open:practical:hardware:sut:stm32:iot_at [2024/04/27 08:14] (current) – [Result validation] ktokarz
@@ Line 1: / Line 1: @@
-====== STM_IoT_AT:  =====
+====== STM_IoT_AT: Programming of the WiFi interface with AT commands =====
 The STM32WB55 SoC doesn't have a WiFi network controller so our STM laboratory stands have the WiFi module based on ESP32-C3 SoC connected by serial port and controlled with AT commands. In this scenario, you will learn how to use these commands.
@@ Line 17: / Line 17: @@
 ==== Task to be implemented ====
-This introductory scenario shows how to use AT commands to control the ESP32-C3 WiFi module connected to the STM laboratory stand. In this scenario, we will use simple AT commands and try to display if their execution finished properly. We will use the LCD to observe the behaviour of the device.
+This introductory scenario shows how to use AT commands to control the ESP32-C3 WiFi module connected to the STM laboratory stand. In this scenario, we will use simple AT commands and try to display if their execution finished properly. We will use the LCD to observe the behaviour of the device. You can use this as the template for the single step of the procedure of establishing a WiFi connection.
 ==== Start ====
@@ Line 49: / Line 49: @@
 We will also declare two strings for comparison with the responses from the WiFi module
 <code c>
-  String compOK;
+String compOK;
-  String compERROR;
+String compERROR;
 </code>
 === Step 3 ===
@@ Line 58: / Line 58: @@
 lcd.begin(16, 2);
 </code>
-And set the two strings :
+And set the two strings for comparison:
 <code c>
 compOK = "OK";
@@ Line 65: / Line 65: @@
 === Step 4 ===
-The AT commands are sent via a serial port connected to the ESP32-C3 module.  At the beginning, we can send an empty command ''AT''. The module should respond ''OK'' if everything works properly or ''ERROR'' if something goes wrong.
+The AT commands are sent via a serial port connected to the ESP32-C3 module. At the beginning, we can send an empty command - "AT". The module should respond "OK" if everything works properly or "ERROR" if something goes wrong.
 <code c>
+// Display the message that the software has started
 lcd.setCursor(0,0);
-    lcd.print("Started");
+lcd.print("Started");
-    delay(1000);
+delay(1000);
-    WiFiSerial.println("AT");
+// Send the "AT" command to the module
-    do{
+WiFiSerial.println("AT");
-      response = WiFiSerial.readStringUntil(0x0A);
-      Serial.print("received: ");
-      Serial.println(response);
-      if (response.startsWith(compERROR)){
-        lcd.setCursor(0,0);
-        lcd.println("Error at x");
-      }
-    } while (!(response.startsWith(compOK)));
-    lcd.setCursor(0,0);
-    lcd.println("Step x OK");
+// Display the command on 1-st line of LCD
+lcd.setCursor(0,0);
+lcd.print("AT              ");
+do {
+  // Read the response till the LF character
+  response = WiFiSerial.readStringUntil(0x0A);
+  // Display the response on 2-nd line of LCD
+  lcd.setCursor(0,1);
+  lcd.print(response);
+  // Repeat until "OK" comes
+} while (!(response.startsWith(compOK)));
 </code>
+This code allows us to observe what AT command has been sent and all the responses. It waits until the "OK" comes which is the text sent by the module after every successful command. If something goes wrong we will see the AT command on the first line and "ERROR" on the second line of LCD, and the program stops. This can help with debugging.
+<note>
+You can use this part of the code in the following scenarios for every AT command to observe their behaviour and easily debug possible errors.
+</note>
 ==== Result validation ====
-Using another node should change the MAC read. Book another device and discover its MAC.
+You should be able to see the "AT" displayed on the upper line of the LCD, and "OK" on the lower line of the LCD. If any error in the communication with the ESP32-C3 module occurs the second line shows "ERROR".
+<note info>
+Because LCD can't properly display some non-visible characters the presented code sometimes shows additional, non-letter characters. It is out of the scope of this scenario to filter these characters out. We leave the task of making visual improvements to your invention.
+</note>
 ===== FAQ =====
-**Can I change MAC?**: Actually, yes, you can. It is not advised, however, because you may accidentally generate an overlapping address that will collide with another device in the same network. You must first explicitly configure the ESP32 chip to work as an AP (Access Point, Server) or STA (WiFi Client) to do it. Sample stub code (for STA) may look as follows:
+**Do I need to write the program for the WiFi module?** No you don't have to. The ESP32-C3 module is flashed with the firmware from Espressif which implements all functionality for WiFi and MQTT. There are other modules which offer similar functionality.\\
-<code c>
+**Can I use a similar WiFi module in my own IoT projects?** Certainly! The universal serial port connects the module so the module can be used with almost every microcontroller as the WiFi network controller.\\
-#include <WiFi.h>
+**Are AT commands the same for all modules available?** The basing AT command set is generally the same, but advanced functionality such as WiFi, MQTT and others can use different syntax for modules from different vendors. Always refer to the original documentation for details.
-#include <esp_wifi.h>
-uint8_t newMAC[] = {0xDE, 0xAD, 0xBE, 0xEF, 0xCA, 0xFE}; //Array of bytes with new MAC
-void setup()
-{
-  WiFi.mode(WIFI_STA);
-  esp_wifi_set_mac(WIFI_IF_STA, &newMAC[0]);
-}
-</code>
 <WRAP noprint>

en/iot-open/practical/hardware/sut/stm32/iot_at.1714040447.txt.gz · Last modified: 2024/04/25 10:20 by ktokarz