Pycom GPy
ESP32 board with LTE CAT-M1/NB-IoT and Wi-Fi - designed for low-power cellular IoT applications.
Pycom GPy Pinout
27 pins| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 0 | LED_BUILTINA11T1 | strapping | adc · touch | |
| 2 | 1 | TXPWM | uart | uart | |
| 3 | 2 | A12T2PWM | strapping | adc · touch | |
| 4 | 3 | RXPWM | uart | uart | |
| 5 | 4 | A10T0PWM | safe | adc · touch | |
| 6 | 5 | LTE_TXPWM | strapping | - | |
| 7 | 12 | SDAA15T5PWM | strapping | adc · touch · i2c | |
| 8 | 13 | SCLSCKA14T4PWM | strapping | adc · touch · spi · i2c | |
| 9 | 14 | A16T6PWM | strapping | adc · touch | |
| 10 | 15 | A13T3PWM | strapping | adc · touch | |
| 11 | 17 | SSPWM | strapping | spi | |
| 12 | 18 | LTE_CTSPWM | safe | - | |
| 13 | 19 | LTE_RTSPWM | safe | - | |
| 14 | 21 | ANT_SELECTPWM | safe | - | |
| 15 | 22 | MOSIPWM | safe | spi | |
| 16 | 23 | LTE_RXPWM | safe | - | |
| 17 | 25 | A18DAC1PWM | safe | adc · dac | |
| 18 | 26 | A19DAC2PWM | safe | adc · dac | |
| 19 | 27 | LTE_WAKEA17T7PWM | safe | adc · touch | |
| 20 | 32 | A4T9PWM | safe | adc · touch | |
| 21 | 33 | A5T8PWM | safe | adc · touch | |
| 22 | 34 | A6 | strapping | adc | |
| 23 | 35 | A7 | strapping | adc | |
| 24 | 36 | A0 | strapping | adc | |
| 25 | 37 | MISOA1 | strapping | adc · spi | |
| 26 | 38 | A2 | strapping | adc | |
| 27 | 39 | A3 | strapping | adc |
Start with these
11 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
15 pins · 12 things to knowLED_BUILTINGPIO0 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.
TXGPIO1 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.
A12GPIO2 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.
RXGPIO3 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.
LTE_TXGPIO5 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.
SDAGPIO12 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.
SCLGPIO13 JTAG clock pin (TCK); also ADC2 channel 4 / Touch4 input. JTAG
Used for JTAG debugging (TCK); avoid using as GPIO if JTAG is needed.
A16GPIO14 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.
A13GPIO15 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.
A6GPIO34 Input-only GPIO (no output driver); ADC1 channel 6. Other
Cannot be used as output (no drive capability); only suitable for analog/digital input.
A7GPIO35MISOGPIO37A2GPIO38A3GPIO39 Input-only GPIOs with ADC1 channels - no output driver Other
Cannot be used as output; only suitable for input.
- A7Input-only GPIO (no output driver); ADC1 channel 7.
- MISOInput-only GPIO (no output); ADC1 channel 1.
- A2Input-only GPIO (no output); ADC1 channel 2.
- A3Input-only GPIO (no output); ADC1 channel 3, Hall sensor VN.
A0GPIO36 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).
Only if you know the tricks
1 pins · 1 thing to knowSSGPIO17 PSRAM clock on WROVER-class modules; in-package flash IO1/DO on ESP32-U4WDH. Also UART2 TX. PSRAM
Wired to the memory die on PSRAM-equipped modules (WROVER, PICO-V3-02) and on in-package-memory chip variants (U4WDH, D0WDRH2-V3); an ordinary GPIO on a plain WROOM-32.
The Pycom GPy pinout brings out 27 GPIO pins - every one of them usable in your project.
For peripherals, I²C is mapped to SDA on GPIO12 and SCL on GPIO13; 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 18 ADC-capable pins for sensors and battery monitoring, 10 capacitive-touch inputs and 2 true DAC outputs.
If you want zero surprises, A10, LTE_CTS, LTE_RTS, ANT_SELECT and 7 more are free of any such role - the safest first picks. 15 of the exposed pins carry boot-time or system duties on the ESP32 (LED_BUILTIN, TX, A12 and 12 more).
Getting started
flash your first firmware in ~2 minutesBoard: ESP32 Wrover Module Flash Size: 8MB (64Mb) Flash Mode: DIO PSRAM: QSPI PSRAM Partition Scheme: 8M with spiffs (3MB APP/1.5MB SPIFFS) Upload Speed: 921600
// toggle GPIO4 - wire an LED and resistor to it
void setup() {
pinMode(4, OUTPUT);
}
void loop() {
digitalWrite(4, HIGH); delay(500);
digitalWrite(4, LOW); delay(500);
}[env:gpy]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
upload_speed = 921600
board_build.arduino.memory_type = qio_qspi
build_flags = -DBOARD_HAS_PSRAMesp32dev - or type it after board =.esp32:
board: esp32dev
variant: esp32
framework:
type: esp-idf
psram:
mode: quad
speed: 80MHz
# blink - GPIO4
output:
- platform: gpio
pin: 4
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 · 55 × 20 mm · vs other ESP32 chips →Dimensions
About this board
At its core is the ESP32 - a dual-core Xtensa with both Bluetooth Classic and BLE.
Expect to pay about $54.95 - above the ~$20 typical for ESP32 boards.
Onboard you'll find 4MB (QSPI) PSRAM and cellular connectivity (Sequans Monarch LTE-M/NB-IoT).
- Triple-network module: LTE-M/NB-IoT (Sequans Monarch), Wi-Fi & BLE
- Onboard ceramic antenna for Wi-Fi/BLE; u.FL connector for the LTE-M/NB-IoT antenna
- No onboard USB - needs Pycom Expansion Board, Pysense or Pytrack to connect
Where to buy
prices are typical street pricesResources
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