T-A7670 Quick Start

Required Libraries

Library	Version	Source
TinyGSM	Latest	GitHub
TinyGPSPlus	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-A7670X environment
4. Click ✓ to build, connect via USB, click → to upload

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Arduino IDE

Board Settings

Setting	Value
Board	ESP32 Dev Module
Upload Speed	921600
CPU Frequency	240 MHz (WiFi)
Flash Size	4 MB (32Mb)
Partition Scheme	Default 4MB with spiffs
PSRAM	Enabled

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Peripheral Examples

LTE Call / SMS (TinyGSM)

#define TINY_GSM_MODEM_A7670
#include <TinyGsmClient.h>

// A7670 UART: RX=26, TX=27, PWR_KEY=4
HardwareSerial modemSerial(1);
TinyGsm modem(modemSerial);

void setup() {
  Serial.begin(115200);
  modemSerial.begin(115200, SERIAL_8N1, 26, 27);
  // Power on modem
  pinMode(4, OUTPUT);
  digitalWrite(4, HIGH); delay(1000);
  digitalWrite(4, LOW);  delay(2000);

  modem.restart();
  Serial.println("Modem: " + modem.getModemInfo());
  modem.gprsConnect("your.apn", "", "");
  Serial.println("Connected: " + String(modem.isGprsConnected()));
}

void loop() { delay(1000); }

GPS (A7670 built-in GNSS)

void setup() {
  // modem already initialized above
  modem.enableGPS();
}

void loop() {
  float lat, lon, speed, alt;
  int vsat, usat;
  if (modem.getGPS(&lat, &lon, &speed, &alt, &vsat, &usat)) {
    Serial.printf("Lat: %.6f Lon: %.6f\n", lat, lon);
  }
  delay(2000);
}

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: Modem not responding?
A: Insert a valid SIM card. Connect the LTE and GPS antennas. Use the PWR_KEY GPIO to power on the A7670 modem.

Q: What cellular standard does A7670 support?
A: A7670 supports LTE Cat-1 with 2G/3G fallback, suitable for voice calls, SMS, and data.