T3-TCXO Quick Start

Required Libraries

Library	Version	Source
RadioLib	Latest	GitHub
U8g2	Latest	Arduino Library Manager

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Arduino

PlatformIO (Recommended)

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

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

3. Open the project, select the T3_V3_0_SX1276_TCXO environment in platformio.ini
4. Click ✓ to build, connect via USB-C, then click → to upload

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Arduino IDE

Board Settings

Setting	Value
Board	ESP32 Dev Module
Upload Speed	921600
Flash Mode	QIO
Flash Size	4MB (32Mb)
Partition Scheme	Default 4MB with spiffs
PSRAM	Enabled

Steps

1. Install Arduino IDE and add ESP32 board support: https://espressif.github.io/arduino-esp32/package_esp32_index.json
2. Clone the LilyGo-LoRa-Series repo and open an example sketch
3. In utilities.h, uncomment T3_V3_0_SX1276_TCXO
4. Select the board settings above and click Upload

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Peripheral Examples

LoRa (SX1276 + TCXO)

#include <RadioLib.h>

// T3-TCXO SX1276: CS=18, IRQ=26, RST=23, DIO1=33
// GPIO12 must be HIGH to enable the TCXO before radio init
SX1276 radio = new Module(18, 26, 23, 33);

void setup() {
  Serial.begin(115200);
  // Enable TCXO
  pinMode(12, OUTPUT);
  digitalWrite(12, HIGH);
  delay(10);

  int state = radio.begin(915.0);
  if (state != RADIOLIB_ERR_NONE) {
    Serial.print("Radio init failed: "); Serial.println(state);
    while (true);
  }
  Serial.println("SX1276 + TCXO ready");
}

void loop() {
  int state = radio.transmit("Hello T3-TCXO");
  if (state == RADIOLIB_ERR_NONE) Serial.println("Sent OK");
  delay(2000);
}

OLED Display (SSD1306)

#include <U8g2lib.h>
#include <Wire.h>

// SSD1306 128×64 I2C, SDA=21, SCL=22
U8G2_SSD1306_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0, U8X8_PIN_NONE);

void setup() {
  u8g2.begin();
}

void loop() {
  u8g2.clearBuffer();
  u8g2.setFont(u8g2_font_ncenB08_tr);
  u8g2.drawStr(0, 20, "T3-TCXO Ready");
  u8g2.sendBuffer();
  delay(1000);
}

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Notes

• SoC: ESP32-Pico-D4 (not standard ESP32 module) — use ESP32 Dev Module board definition
• TCXO: The onboard TCXO (±0.5 ppm) provides temperature-stable frequency; set TCXO enable pin (GPIO12) HIGH before LoRa initialization
• PSRAM: 2 MB PSRAM is present — enable it in board settings
• Power: Supports USB-C, 3.7 V Li-Po battery, and solar input

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FAQ

Q: LoRa frequency drifts at temperature extremes? A: The TCXO is the fix for this — ensure GPIO12 is driven HIGH to enable it before calling radio.begin().

Q: Cannot find the board after connecting USB-C? A: The ESP32-Pico-D4 uses a standard USB-serial bridge — check Device Manager for the COM port and install CH34x or CP210x drivers if needed.