ESP8266 (ESP-01/01S) Microcontrollers


Difference ESP01/01s and ESP8266 NodeMCU/D1 Wemos

ESP01/01s does not have the CH340C USB to UART component that uploads the Arduino IDE sketch compiled in binary from PC’s local storage to ESP01/01s external flash memory (512Kb (4Mbit) or 1MB (8MBit) via PC’s USB port.

External Flash Memory (ESP01/ESP01s)

512 Kb / 4Mbit (ESP-01)

1 Mb / 8Mbit (EPS-01s)

Note: New ESP01 maybe shipped with 1 Mb / 8Mbit

ESP01/ESP01S Pin Out

Blue LED (built-in aka Comm LED)

The blue LED is on TX line (GPIO 01). Serial.println() in your sketch will NOT work at same time.


ESP8266EX Datasheet

ESP8266 Wifi Community