T-SIM7080-S3 Quick Start

Required Libraries

Library	Version	Source
TinyGSM	Latest	GitHub
XPowersLib	Latest	GitHub

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Arduino

PlatformIO (Recommended)

1. Install VS Code and the PlatformIO IDE extension
2. Clone the repository:

   git clone https://github.com/Xinyuan-LilyGO/LilyGo-Modem-Series.git

3. Open platformio.ini and select the T-SIM7080-S3 environment
4. Click ✓ to build, connect via USB-C, click → to upload

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Arduino IDE

Board Settings

Setting	Value
Board	ESP32S3 Dev Module
Upload Speed	921600
USB CDC On Boot	Enable
CPU Frequency	240 MHz (WiFi)
Flash Size	16 MB (128Mb)
Partition Scheme	16M Flash (3MB APP/9.9MB FATFS)
PSRAM	OPI PSRAM

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Peripheral Examples

NB-IoT / LTE-M Data (TinyGSM)

#define TINY_GSM_MODEM_SIM7080
#include <TinyGsmClient.h>

// SIM7080G UART: RX=4, TX=5, PWR_KEY=12
HardwareSerial modemSerial(1);
TinyGsm modem(modemSerial);

void setup() {
  Serial.begin(115200);
  modemSerial.begin(115200, SERIAL_8N1, 4, 5);
  // Power on modem
  pinMode(12, OUTPUT);
  digitalWrite(12, HIGH); delay(1000);
  digitalWrite(12, LOW);  delay(3000);

  modem.restart();
  Serial.println("Modem: " + modem.getModemInfo());
  modem.setNetworkMode(38); // LTE-M + NB-IoT
  modem.gprsConnect("your.apn", "", "");
  Serial.println("Connected: " + String(modem.isGprsConnected()));
}

void loop() { delay(1000); }

PMU (AXP2101 via XPowersLib)

#include <XPowersLib.h>

XPowersPMU pmu;

void setup() {
  Serial.begin(115200);
  Wire.begin();
  if (!pmu.begin(Wire, AXP2101_SLAVE_ADDRESS)) {
    Serial.println("PMU init failed");
    return;
  }
  Serial.printf("Battery: %d mV\n", pmu.getBattVoltage());
}

void loop() { delay(1000); }

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FAQ

Q: Upload keeps failing?
A: Hold BOOT, press and release RST, then release BOOT to enter download mode.

Q: SIM7080G modem not responding?
A: Insert a valid nano SIM with NB-IoT or LTE-M service. Connect the cellular antenna. Power on the modem with the PWR key GPIO before sending AT commands.