SIM800L GSM/GPRS Module
Compact GSM/GPRS module based on SIMCom SIM800L chip. Features a built-in SIM card slot and antenna connector. Communicates via UART using AT commands. Operates at 3.4V–4.4V supply (must NOT be powered from 3.3V LDO; use a boost converter such as MT3608).
Pinout
- VCC
Supply voltage 3.4V–4.4V (typically ~4.0V from MT3608 boost converter). Peak 2A burst — use dedicated external supply with large decoupling capacitor (100–470uF).
Type · PowerVoltage · 3.7 - GND
Common ground shared with ESP32 and power supply.
Type · Ground - TX
UART transmit pin (output from SIM800L to ESP32 RX). Logic level ~2.8V, compatible with ESP32 3.3V input threshold — no level shifting needed on this line.
Type · UART - RX
UART receive pin (input to SIM800L from ESP32 TX). Logic level ~2.8V. Drive via resistor voltage divider from ESP32 TX (3.3V → ~2.8V) to protect SIM800L input.
Type · UART - RST
Active-low hardware reset pin. Can be driven by ESP32 GPIO (3.3V logic).
Type · Control
| Pin | Type | Function | Voltage |
|---|---|---|---|
| VCC | Power | Supply voltage 3.4V–4.4V (typically ~4.0V from MT3608 boost converter). Peak 2A burst — use dedicated external supply with large decoupling capacitor (100–470uF). | 3.7 |
| GND | Ground | Common ground shared with ESP32 and power supply. | |
| TX | UART | UART transmit pin (output from SIM800L to ESP32 RX). Logic level ~2.8V, compatible with ESP32 3.3V input threshold — no level shifting needed on this line. | |
| RX | UART | UART receive pin (input to SIM800L from ESP32 TX). Logic level ~2.8V. Drive via resistor voltage divider from ESP32 TX (3.3V → ~2.8V) to protect SIM800L input. | |
| RST | Control | Active-low hardware reset pin. Can be driven by ESP32 GPIO (3.3V logic). |
Pin details
5 connections- VCC
Supply voltage 3.4V–4.4V (typically ~4.0V from MT3608 boost converter). Peak 2A burst — use dedicated external supply with large decoupling capacitor (100–470uF).
PowerVoltage · 3.7 - GND
Common ground shared with ESP32 and power supply.
Ground - TX
UART transmit pin (output from SIM800L to ESP32 RX). Logic level ~2.8V, compatible with ESP32 3.3V input threshold — no level shifting needed on this line.
UART - RX
UART receive pin (input to SIM800L from ESP32 TX). Logic level ~2.8V. Drive via resistor voltage divider from ESP32 TX (3.3V → ~2.8V) to protect SIM800L input.
UART - RST
Active-low hardware reset pin. Can be driven by ESP32 GPIO (3.3V logic).
Control
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