Pinout ESP-01

The ESP8266-01, or ESP-01, is a low-cost and widely used WiFi microcontroller developed by Espressif Systems. It is particularly popular with hobbyists and developers of IoT (Internet of Things) applications due to its low cost and ease of integration.

Fundamentals

The ESP-01 is a module that contains the ESP8266 microcontroller, together with a small number of peripheral components. It enables a microcontroller to connect to a WiFi network and run simple network protocols. The ESP8266-01 (ESP-01) is often used as a WiFi transceiver to add wireless networking capability to existing projects.

Properties

• CPU:32-bit Tensilica L106 with a clock frequency of up to 80 MHz.
• Memory: 64 KB instruction RAM, 96 KB data RAM.
• Memory capacity: 512 KB flash memory.
• WiFi: 802.11 b/g/n Standard, integrated TCP/IP stack.
• Power supply: 3.0V to 3.6V.
• Operating system: Supports FreeRTOS.

Internals

The ESP8266-01 (ESP-01) has a simple architecture that allows WiFi connectivity to be easily integrated into microcontroller projects. The microcontroller includes integrated analog and digital peripherals as well as WiFi functionalities that allow it to be used in a variety of networking applications.

• Integrated TCP/IP stack: Enables direct connection to the Internet.
• GPIO: Two general purpose input/output pins that can be used for a variety of applications.
• UART: Universal asynchronous receiver/transmitter for serial communication

Connections

The ESP8266-01 has a total of 8 pins:

1. VCC: Power supply (3.3V).
2. GND: Ground.
3. TX: UART transmitter. (GPIO 1)
4. RX: UART-Receiver. (GPIO 3)
5. CH_PD (EN): Chip Enable, must be set to HIGH for the module to function.
6. GPIO0: General input/output pin, can also be used to activate flash mode.
7. GPIO2: General input/output pin.
8. RST: Reset pin to reset the microcontroller.

GPIO 1and 3 on the ESP8266-01 are special pins that play a dual role. They can be used both as GPIO pins and as UART TX/RX pins. For serial communication, they should remain free and not be used as IO pins.

Deep Sleep

Deep sleep mode is an energy-saving mode of the ESP8266-01 that allows power consumption to be significantly reduced by turning off the main processor and most peripherals. This is particularly useful for battery-powered applications that need to bridge long periods without power supply operation.

• Activation of deep sleep mode: Deep sleep mode can be activated by a simple command in the firmware, for example:

SP.deepSleep(time_in_microseconds);

Wake-up mode: The ESP8266-01 can wake up automatically after a predefined time or be woken up by an external event (e.g. GPIO interrupt).

Using the GPIO 16 pin: To use the deep sleep mode, GPIO16 must be connected to the RESET pin so that the module can wake up again after the deep sleep time has elapsed.

Example of deep sleep

Here is a simple example that puts the ESP8266-01 into deep sleep mode for 10 seconds:

void setup() {
  Serial.begin(115200);
  Serial.println("Going to sleep now");
  ESP.deepSleep(10 * 1000000); // 10 seconds in microseconds
}

void loop() {
  // This code is not executed because the ESP8266 is in deep sleep mode
}

Summary

The ESP8266-01 is a versatile and cost-effective module that is ideal for IoT applications. With its basic GPIO connections and integrated WiFi functionality, it is ideal for home automation, sensor monitoring and other wireless projects. The deep sleep mode allows power consumption to be minimized, making it particularly attractive for battery-powered applications.