Originally, the ESP-01S was developed around the ESP8266 microchip, which made its debut in 2014. The ESP8266 is a 32-bit microcontroller created by Espressif Systems. It operates at 80MHz and can be overclocked to 160MHz. The ESP-01S was primarily used as a Wi-Fi module for other microcontrollers, such as the Arduino Uno R3. Communication between the Arduino Uno R3 and the ESP-01S occurred through a serial port using AT commands. These AT commands resembled the old DOS command-line interface. The Arduino Uno R3 sent these commands to the ESP-01S, which in turn accessed Wi-Fi data and returned results via the serial port.
As the ESP-01S boasts 17 GPIO pins and a significantly faster CPU compared to the 8-bit Arduino Uno R3 MCU, it eventually found use as a standalone MCU in the Arduino IDE. In this tutorial, we will explore using the ESP-01S as a standalone MCU in the Arduino IDE and programming it using the C language, much like we would with the Arduino Uno R3.
ESP8266 vs. ESP8285
The ESP8285 made its debut in 2016 and is fully compatible with the ESP8266. The primary distinction lies in the fact that the ESP8285 comes with built-in 1MB Flash memory, whereas the ESP8266 lacks integrated flash memory. Typically, the ESP-01S is equipped with 1MB Flash memory. While the ESP8266 serves as the core, an external RAM IC is required to communicate with the ESP8266 via the SPI interface. In contrast, the ESP8285 eliminates the need for an external RAM IC, resulting in a smaller PCB footprint and less power consumption.
At Lonely Binary, we offer both the ESP-01S with the ESP8266 and ESP8285 as the core options. Our ESP-01S with the ESP8266 boasts 4MB Flash memory, four times that of the standard version. If you engage in extensive coding or require Over-The-Air (OTA) capabilities, we highly recommend the ESP-01S with ESP8266 4MB version. On the other hand, if you seek longer battery life, the ESP-01S with ESP8285 1MB is an excellent choice due to its reduced need for external components, resulting in lower power consumption.