TTGO T1
Classic ESP32 TTGO board with LiPo support and headers - great for basic wireless development and IoT builds.
TTGO T1 Pinout
36 pins
| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | - | GND | ground | - | Ground |
| 2 | 23 | GPIO23MOSI | safe | spi | VSPI MOSI |
| 3 | 22 | GPIO22SCL | safe | i2c | Default I2C SCL, onboard LED (LED_BUILTIN) |
| 4 | 1 | GPIO1TX | uart | uart | UART0 TX |
| 5 | 3 | GPIO3RX | uart | uart | UART0 RX |
| 6 | 21 | GPIO21SDA | safe | i2c | Default I2C SDA |
| 7 | - | 5V | power | - | 5V from USB / power input |
| 8 | 19 | GPIO19MISO | safe | spi | VSPI MISO |
| 9 | 18 | GPIO18SCK | safe | spi | VSPI SCK |
| 10 | 5 | GPIO5SS | strapping | spi | VSPI SS |
| 11 | 17 | GPIO17 | safe | - | General-purpose IO |
| 12 | 16 | GPIO16 | safe | - | General-purpose IO |
| 13 | 4 | GPIO4 | safe | adc · touch | ADC2_CH0, Touch0 |
| 14 | 0 | GPIO0 | strapping | adc · touch | ADC2_CH1, Touch1 |
| 15 | 2 | GPIO2SD MISO | strapping | adc · touch · spi | microSD MISO, ADC2_CH2, Touch2 |
| 16 | 15 | GPIO15SD MOSI | strapping | adc · touch · spi | microSD MOSI, ADC2_CH3, Touch3 |
| 17 | 8 | SD1GPIO8 | strapping | - | Flash pin - do not use |
| 18 | 7 | SD0GPIO7 | strapping | - | Flash pin - do not use |
| 19 | - | 3V33.3V | power | - | 3.3V regulated output |
| 20 | - | RSTEN | control | - | Chip enable / reset (active LOW) |
| 21 | 36 | SVPGPIO36 | strapping | adc | ADC1_CH0, input only |
| 22 | 39 | SVNGPIO39 | strapping | adc | ADC1_CH3, input only |
| 23 | 34 | GPIO34 | strapping | adc | ADC1_CH6, input only |
| 24 | 35 | GPIO35 | strapping | adc | ADC1_CH7, input only |
| 25 | 32 | GPIO32 | safe | adc · touch | ADC1_CH4, Touch9 |
| 26 | 33 | GPIO33 | safe | adc · touch | ADC1_CH5, Touch8 |
| 27 | 25 | GPIO25 | safe | adc · dac | DAC1, ADC2_CH8 |
| 28 | 26 | GPIO26 | safe | adc · dac | DAC2, ADC2_CH9 |
| 29 | 27 | GPIO27 | safe | adc · touch | ADC2_CH7, Touch7 |
| 30 | 14 | GPIO14SD SCK | strapping | adc · touch · spi | microSD SCK, ADC2_CH6, Touch6 |
| 31 | 12 | GPIO12 | strapping | adc · touch | ADC2_CH5, Touch5 |
| 32 | - | GND | ground | - | Ground |
| 33 | 13 | GPIO13SD CS | strapping | adc · touch · spi | microSD CS, ADC2_CH4, Touch4 |
| 34 | 9 | SD2GPIO9 | strapping | - | Flash pin - do not use |
| 35 | 10 | SD3GPIO10 | strapping | - | Flash pin - do not use |
| 36 | 11 | CMDGPIO11 | strapping | - | Flash pin - do not use |
Start with these
13 pins with no boot or system involvementFreely assignable - no strapping, flash, USB or JTAG duties. Ideal first picks for buttons, sensors and LEDs.
Fine - with a little care
13 pins · 12 things to knowGPIO1 Default UART0 TX pin for USB-serial programming and console. UART
Connected to on-board USB-UART for uploading and logs; drives serial output at boot, so using as GPIO can disrupt programming or console.
GPIO3 Default UART0 RX pin for USB-serial programming (console input). UART
Used for receiving data from USB-UART (programming); also pulled HIGH at boot for console communication, so using as GPIO can disrupt uploads.
GPIO5 Bootstrapping pin; internal pull-up; VSPI CS0 (default SPI chip-select); acts as FSPIWP (flash write-protect) on internal-flash variants. Strapping
Must be HIGH during boot; if pulled LOW at reset, alters SDIO slave timing and may prevent normal boot.
GPIO0 Bootstrapping pin (enter bootloader when low); internal pull-up. Strapping
Must be HIGH during boot for normal startup; if held LOW on reset, forces flash programming mode.
GPIO2 Bootstrapping pin (must be low or floating at reset); internal pull-down. Strapping
If driven HIGH on reset (while IO0 is LOW), selects an unsupported SDIO boot mode, causing boot failure.
GPIO15 Bootstrapping pin; JTAG TDO; controls UART0 boot log output; also HSPICS0 (secondary SPI CS). Strapping
Keep HIGH during boot (internal PU); if LOW on reset, bootloader log is silenced and boot mode may change.
SVPGPIO36 Input-only GPIO (no output); ADC1 channel 0, Hall sensor VP. Other
Cannot be used as output; only suitable for input (e.g., analog read).
SVNGPIO39GPIO35 Input-only GPIOs with ADC1 channels - no output driver Other
Cannot be used as output; only suitable for input.
- SVNInput-only GPIO (no output); ADC1 channel 3, Hall sensor VN.
- GPIO35Input-only GPIO (no output driver); ADC1 channel 7.
GPIO34 Input-only GPIO (no output driver); ADC1 channel 6. Other
Cannot be used as output (no drive capability); only suitable for analog/digital input.
GPIO14 JTAG mode select pin (TMS); also HSPI CLK and PWM-capable GPIO. JTAG
Used for JTAG debugging (TMS); driving it as GPIO may interfere with JTAG or produce spurious signals at boot.
GPIO12 Bootstrapping pin; JTAG TDI; sets flash voltage (VDD_SDIO); also HSPIQ (flash data line). Strapping
Keep LOW during boot (internal PD); pulling HIGH at reset selects 1.8V flash mode, causing flash brownout if 3.3V flash is used.
GPIO13 JTAG clock pin (TCK); also ADC2 channel 4 / Touch4 input. JTAG
Used for JTAG debugging (TCK); avoid using as GPIO if JTAG is needed.
Only if you know the tricks
5 pins · 3 things to knowSD1GPIO8SD0GPIO7 SPI flash data lines SD0 and SD1 Flash
Used for internal flash/PSRAM data; not available for general GPIO.
- SD1Connected to SPI flash data 1 (SD1).
- SD0Connected to SPI flash data 0 (SD0).
SD2GPIO9SD3GPIO10 SPI flash/PSRAM data lines SD2 and SD3 (flash HOLD and WP) Flash
Used by internal flash/PSRAM; typically not exposed on modules, avoid using as GPIO.
- SD2Connected to SPI flash/PSRAM data 2 (SD2, flash HOLD).
- SD3Connected to SPI flash/PSRAM data 3 (SD3, flash WP).
CMDGPIO11 Connected to SPI flash command/CS (CMD/CS0). Flash
Used by internal flash (chip select/command); not available for general use.
The TTGO T1 breaks out 36 pins in total: 31 GPIO for your project, with GND, 5V and 3V3 handling power.
For peripherals, I²C is mapped to SDA on GPIO21 and SCL on GPIO22; the SPI bus (MOSI, MISO, SCK, SS) is broken out in full; TX/RX on GPIO1 and GPIO3 cover serial logging and flashing.
On the analog side there are 16 ADC-capable pins for sensors and battery monitoring, 10 capacitive-touch inputs and 2 true DAC outputs.
If you want zero surprises, GPIO23, GPIO22, GPIO21, GPIO19 and 9 more are free of any such role - the safest first picks. 13 of the exposed pins carry boot-time or system duties on the ESP32 (GPIO1, GPIO3, GPIO5 and 10 more).
Getting started
flash your first firmware in ~2 minutesBoard: ESP32 Dev Module Flash Size: 4MB (32Mb) Flash Mode: DIO Partition Scheme: Default 4MB with spiffs (1.2MB APP/1.5MB SPIFFS) Upload Speed: 921600
// toggle GPIO23 - wire an LED and resistor to it
void setup() {
pinMode(23, OUTPUT);
}
void loop() {
digitalWrite(23, HIGH); delay(500);
digitalWrite(23, LOW); delay(500);
}[env:ttgo-t1]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
upload_speed = 921600esp32dev - or type it after board =.esp32:
board: esp32dev
variant: esp32
framework:
type: esp-idf
# blink - GPIO23
output:
- platform: gpio
pin: 23
id: led_out
light:
- platform: binary
name: "LED"
output: led_outesp32dev (same ids as PlatformIO).esptool.py --chip esp32 --port /dev/ttyACM0 \
--baud 921600 write_flash 0x1000 firmware.bin--port = your /dev/tty* (macOS/Linux) or COMx (Windows).Specifications
ESP32 · vs other ESP32 chips →About this board
At its core is the ESP32 - a dual-core Xtensa with both Bluetooth Classic and BLE.
Expect to pay about $7.00 - less than the ~$20 most ESP32 boards go for.
31 GPIO are broken out - more than most ESP32 boards, so the pin budget is rarely the constraint.
Onboard you'll find a microSD slot, battery charging via JST 1.25mm and Reset buttons.
- Power on/off switch
Where to buy
prices are typical street pricesResources
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