TTGO T-Call (LilyGO) Development Board
Code name: ESP32_DEV
TTGO T-Call (LilyGO) development board is based on esp32 microcontroller and uses xtensa architecture. This board has a maximum CPU frequency of 240 MHz and a flash size of 4MB.
About TTGO T-Call (LilyGO)
The TTGO T-Call is a powerful ESP32 development board designed for cellular IoT applications, featuring integrated GSM/GPRS connectivity alongside Wi-Fi 802.11 b/g/n and Bluetooth 4.2 + BLE. 📶📱
Powered by an ESP32 dual-core processor at 240 MHz, with 4MB/8MB flash memory and 8MB PSRAM, it's optimized for demanding IoT projects requiring reliable remote connectivity. ⚡
The board supports multiple cellular modules: SIM800H (2G GSM/GPRS) and A7670E (LTE/4G) for global cellular communication. It includes a nano SIM card slot, GSM antenna connector, and comprehensive cellular interfaces. 🔌
Features USB Type-C for programming, Li-Po battery support with charging circuit, and extensive GPIO pins supporting ADC, DAC, PWM, I2C, SPI, UART, I2S, and CAN interfaces. Operating at 3.3V with robust power management. 🔋
Where to Buy TTGO T-Call (LilyGO)
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$26.52
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TTGO T-Call (LilyGO) Technical Specifications
🔌 USB
🛰️ Connectivity
🧠 Microcontroller
✨ Features
- Cellular Connectivity
- Li-Po Battery Support
- Nano SIM Slot
- 30 digital IO pins
- 16 external interrupt pins
- 16 analog input pins
- 19 PWM pins
TTGO T-Call (LilyGO) Pinout
The TTGO T-Call pinout provides extensive connectivity options for cellular IoT projects. Power management includes 5V input, 3.3V regulated output, and battery charging circuitry.
Cellular connectivity features dedicated SIM card slot and GSM ANT antenna connector. Communication interfaces include multiple UART channels for cellular module communication, plus standard ESP32 GPIO pins.
GPIO pins support digital I/O, ADC (18 channels), PWM, and multiple protocols. The board includes EN reset button and comprehensive peripheral interfaces for sensor integration and external device connectivity.
✅ Safe Pins to Use
For general GPIO usage, these are the safest and most flexible choices:
Why Are These Pins Safe?
- Not involved in bootstrapping → No impact on device boot mode or system startup
- Not linked to flash memory or PSRAM → Won't interfere with storage or memory access
- Not dedicated to USB or JTAG → Free for general use without affecting debugging
- No special hardware connections → Freely assignable without internal conflicts
⚠️ Pins to Avoid or Use with Caution
Some pins are reserved for critical functions like bootstrapping, JTAG debugging, USB communication, and flash memory operations. Misusing these pins may lead to boot failures, programming issues, USB conflicts, or disruptions in flash storage.
Critical Pin Categories:
- 🛠️ Strapping Pins: Control boot behavior and flash voltage selection
- 🔗 JTAG Debugging Pins: Required for low-level debugging
- 🔌 USB Communication Pins: Used for USB Serial/JTAG communication
- ⚡ Flash Memory & SPI Pins: Connected to SPI flash memory and PSRAM
- 📡 UART Serial Communication Pins: Used for debugging and firmware uploads
| PIN | Label | Reason | Function |
|---|---|---|---|
| IO0 | GPIO0 | Must be HIGH during boot for normal startup; if held LOW on reset, forces flash programming mode. | 🛠️ Strapping |
| IO2 | GPIO2 | If driven HIGH on reset (while IO0 is LOW), selects an unsupported SDIO boot mode, causing boot failure. | 🛠️ Strapping |
| IO4 | GPIO4 | Sampled at reset for boot config; should not be driven at boot (affects boot mode timing). | 🛠️ Strapping |
| IO5 | GPIO5 | Must be HIGH during boot; if pulled LOW at reset, alters SDIO slave timing and may prevent normal boot. | 🛠️ Strapping |
| IO12 | MTDI (GPIO12) | Keep LOW during boot (internal PD); pulling HIGH at reset selects 1.8V flash mode, causing flash brownout if 3.3V flash is used. | 🛠️ Strapping |
TTGO T-Call Cellular Modules
📱 Available Models
- SIM800H: 2G GSM/GPRS module supporting quad-band GSM (850/900/1800/1900MHz) and GPRS data transmission
- A7670E: LTE Cat.1 module with global LTE bands, ideal for IoT applications requiring higher data speeds
- SIM800L: Compact 2G module option for basic cellular connectivity
⚠️ Important Notes
The A7670E module has LTE band limitations in some regions (e.g., US LTE bands may not be fully supported). Check cellular band compatibility for your location. SIM800H provides reliable 2G connectivity but limited data speeds.
💡 Perfect For
Ideal for remote monitoring, asset tracking, smart agriculture, and any IoT project requiring cellular connectivity with WiFi/Bluetooth backup options.
TTGO T-Call (LilyGO) Pin Mappings
This development board provides 30 digital IO pins, out of which 16 can be used as external interrupt pins , 16 as analog input pins and 19 pins have Pulse-Width Modulation (PWM) .
| Pin | Function | ESP Pin | Input/Output | Description |
|---|---|---|---|---|
| 4 | TX | GPIO17 | OUTPUT | UART2 TX for Cellular Module |
| 5 | RX | GPIO16 | INPUT | UART2 RX for Cellular Module |
| 6 | IO0 | GPIO0 | BIDIRECTIONAL | GPIO0, Boot Mode Selection |
| 7 | IO2 | GPIO2 | BIDIRECTIONAL | GPIO2, General Purpose I/O |
| 8 | IO4 | GPIO4 | BIDIRECTIONAL | GPIO4, General Purpose I/O |
| 9 | IO5 | GPIO5 | BIDIRECTIONAL | GPIO5, General Purpose I/O |
| 10 | IO12 | GPIO12 | BIDIRECTIONAL | GPIO12, ADC or GPIO |
| 11 | IO13 | GPIO13 | BIDIRECTIONAL | GPIO13, ADC or GPIO |
| 12 | IO14 | GPIO14 | BIDIRECTIONAL | GPIO14, ADC or GPIO |
| 13 | IO15 | GPIO15 | BIDIRECTIONAL | GPIO15, ADC or GPIO |
| 14 | IO16 | GPIO16 | BIDIRECTIONAL | GPIO16, General Purpose I/O |
| 15 | RXD0 | GPIO3 | INPUT | UART0 Receive |
| 16 | TXD0 | GPIO1 | OUTPUT | UART0 Transmit |
| 17 | IO17 | GPIO17 | BIDIRECTIONAL | GPIO17, General Purpose I/O |
| 18 | IO18 | GPIO18 | BIDIRECTIONAL | GPIO18, General Purpose I/O |
| 19 | IO19 | GPIO19 | BIDIRECTIONAL | GPIO19, General Purpose I/O |
| 20 | IO21 | GPIO21 | BIDIRECTIONAL | GPIO21, I2C SDA |
| 21 | IO22 | GPIO22 | BIDIRECTIONAL | GPIO22, I2C SCL |
| 22 | IO23 | GPIO23 | BIDIRECTIONAL | GPIO23, SPI MOSI |
| 23 | IO25 | GPIO25 | BIDIRECTIONAL | GPIO25, DAC1 |
| 24 | IO26 | GPIO26 | BIDIRECTIONAL | GPIO26, DAC2 |
| 25 | IO27 | GPIO27 | BIDIRECTIONAL | GPIO27, ADC |
| 26 | IO32 | GPIO32 | BIDIRECTIONAL | GPIO32, ADC |
| 27 | IO33 | GPIO33 | BIDIRECTIONAL | GPIO33, ADC |
| 28 | IO34 | GPIO34 | INPUT | GPIO34, ADC Input Only |
| 29 | IO35 | GPIO35 | INPUT | GPIO35, ADC Input Only |
TTGO T-Call (LilyGO) Pins Mapping Arduino IDE
Below you can find the TTGO T-Call (LilyGO) pinout. This development board provides 30 digital IO pins, out of which 16 can be used as external interrupt pins, 16 as analog input pins and 19 pins have Pulse-Width Modulation (PWM).
| Pin | Analog | Touch | PWM | Other |
|---|---|---|---|---|
| 0 | T1 | |||
| 1 | PWM | TX | ||
| 2 | A12 | T2 | PWM | |
| 3 | PWM | RX | ||
| 4 | A10 | T0 | PWM | |
| 5 | PWM | |||
| 12 | A15 | T5 | PWM | |
| 13 | A14 | T4 | PWM | |
| 14 | A16 | T6 | PWM | |
| 15 | A13 | T3 | PWM | |
| 16 | PWM | |||
| 17 | PWM | |||
| 18 | PWM | |||
| 19 | PWM | |||
| 21 | PWM | SDA | ||
| 22 | PWM | SCL | ||
| 23 | PWM | MOSI | ||
| 25 | A18 | DAC1 | ||
| 26 | A19 | DAC2 | ||
| 27 | A17 | T8 | PWM | |
| 32 | A4 | T9 | PWM | |
| 33 | A5 | T10 | PWM | |
| 34 | A6 | INPUT | ||
| 35 | A7 | INPUT |
Default Tools for TTGO T-Call (LilyGO)
| Bootloader tool | esptool_py |
| Uploader tool | esptool_py |
| Network uploader tool | esp_ota |
| Bootloader address | 0x1000 |
| Flash mode | dio |
| Boot mode | dio |
| Maximum upload size | 1280 Kb (1310720 B) |
| Maximum data size | 320 Kb (327680 B) |
The TTGO T-Call (LilyGO) development board by default uses esptool_py uploader tool, esp_ota network uploader tool for Over-the-air (OTA) uploads and esptool_py bootloader tool. The bootloader starts at address "0x1000". Flash mode and boot mode for TTGO T-Call (LilyGO) development board by default is dio and dio respectively.
