LoPy4

Upgraded LoPy with BLE and improved specs - perfect for versatile multi-network IoT applications.

LoPy4 board
55 × 20 mm
ESP32
MCU
240MHz
clock
4MB
flash
520KB
SRAM
26· 18 ADC
GPIO
BLE 4.2+ WiFi
radio
On this page

Pinout

26 pins
View:
PinGPIOLabelsStatusCapabilitiesNotes
10LED_BUILTINA11T1strappingadc · touch
21TXPWMuartuart
32A12T2PWMstrappingadc · touch
43RXPWMuartuart
54A10T0PWMstrappingadc · touch
65LORA_SCKPWMstrapping-
712SDAA15T5PWMstrappingadc · touch · i2c
813SCLSCKA14T4PWMstrappingadc · touch · spi · i2c
914A16T6PWMstrappingadc · touch
1015A13T3PWMstrappingadc · touch
1118LORA_CSSSPWMsafespi
1219LORA_MISOPWMsafe-
1321ANT_SELECTPWMsafe-
1422MOSIPWMsafespi
1523LORA_IRQPWMsafe-
1625A18DAC1PWMsafeadc · dac
1726A19DAC2PWMsafeadc · dac
1827LORA_MOSIA17T7PWMsafeadc · touch
1932A4T9PWMsafeadc · touch
2033A5T8PWMsafeadc · touch
2134A6strappingadc
2235A7strappingadc
2336A0strappingadc
2437MISOA1strappingadc · spi
2538A2strappingadc
2639A3strappingadc

Start with these

10 pins with no boot or system involvement
LORA_CSSSLORA_MISOPWMANT_SELECTPWMMOSIPWMLORA_IRQPWMA18DAC1A19DAC2LORA_MOSIA17A4T9A5T8

Freely assignable - no strapping, flash, USB or JTAG duties. Ideal first picks for buttons, sensors and LEDs.

Fine - with a little care

sampled at boot or shared with debug/serial
PinLabelWhat to knowRole
LED_BUILTINGPIO0Must be HIGH during boot for normal startup; if held LOW on reset, forces flash programming mode.Strapping
A12GPIO2If driven HIGH on reset (while IO0 is LOW), selects an unsupported SDIO boot mode, causing boot failure.Strapping
A10GPIO4Sampled at reset for boot config; should not be driven at boot (affects boot mode timing).Strapping
LORA_SCKGPIO5Must be HIGH during boot; if pulled LOW at reset, alters SDIO slave timing and may prevent normal boot.Strapping
SDAMTDI (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
SCLMTCK (GPIO13)Used for JTAG debugging (TCK); avoid using as GPIO if JTAG is needed.Other
A16MTMS (GPIO14)Used for JTAG debugging (TMS); driving it as GPIO may interfere with JTAG or produce spurious signals at boot.Other
A13MTDO (GPIO15)Keep HIGH during boot (internal PU); if LOW on reset, bootloader log is silenced and boot mode may change.Strapping
A6GPIO34Cannot be used as output (no drive capability); only suitable for analog/digital input.Other
A7GPIO35Cannot be used as output; only suitable for input.Other
A0GPIO36 (SENSOR_VP)Cannot be used as output; only suitable for input (e.g., analog read).Other
MISOGPIO37 (SENSOR_CAPP)Cannot be used as output; only suitable for input.Other
A2GPIO38 (SENSOR_CAPN)Cannot be used as output; only suitable for input.Other
A3GPIO39 (SENSOR_VN)Cannot be used as output; only suitable for input.Other

Only if you know the tricks

wired to flash or USB - expect a fight
PinLabelWhat to knowRole
TXU0TXD (GPIO1)Connected to on-board USB-UART for uploading and logs; drives serial output at boot, so using as GPIO can disrupt programming or console.USB
RXU0RXD (GPIO3)Used for receiving data from USB-UART (programming); also pulled HIGH at boot for console communication, so using as GPIO can disrupt uploads.USB
These are recommendations, not hard rules - with the right pull-ups, timing and boot-state awareness most pins can be made to work. When in doubt, start green.
Pinout notes The LoPy4 pinout brings out 26 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…

The LoPy4 pinout brings out 26 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, LORA_CS, LORA_MISO, ANT_SELECT, MOSI and 6 more are free of any such role - the safest first picks. 14 of the exposed pins carry boot-time or system duties on the ESP32 (LED_BUILTIN, A12, A10 and 11 more).

Getting started

flash your first firmware in ~2 minutes
Tool:
1
Connect over USB
Install your USB-serial driver (CH340 / CP210x) if no port appears. Not detected? Hold BOOT while plugging in.
2
Match & flash
Set the Tools options shown, then click Upload.
3
Verify it runs
The onboard LED on GPIO18 blinks - swap the pin if your board's LED differs.
Set these in Tools · leave everything else at default
Arduino IDE 2.x — Tools Copy
Board: "ESP32 Wrover Module"
Flash Size: "4MB (32Mb)"
Flash Mode: "DIO"
PSRAM: "QSPI PSRAM"
Partition Scheme: "Default 4MB with spiffs (1.2MB APP / 1.5MB SPIFFS)" (default)
Upload Speed: "921600"
▸ every other Tools option — leave at default
Board: ESP32 Wrover Module
Flash Size: 4MB (32Mb)
Flash Mode: DIO
PSRAM: QSPI PSRAM
Partition Scheme: Default 4MB with spiffs (1.2MB APP / 1.5MB SPIFFS)
Upload Speed: 921600
Find it: Tools ▸ Board ▸ ESP32 Arduino ▸ ESP32 Wrover Module
blink.ino Copy
// blink the onboard LED
void setup() {
  pinMode(18, OUTPUT);
}
void loop() {
  digitalWrite(18, HIGH); delay(500);
  digitalWrite(18, LOW);  delay(500);
}
board to selectesp32dev⧉ copy
platformio.ini Copy
[env:lopy4]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
upload_speed = 921600
board_build.arduino.memory_type = qio_qspi
build_flags = -DBOARD_HAS_PSRAM
Find it: PlatformIO Home ▸ Boards, search esp32dev — or type it after board =.
board to selectesp32dev⧉ copy
device.yaml Copy
esp32:
  board: esp32dev
  variant: lopy4
  framework:
    type: esp-idf
psram:
  mode: quad
  speed: 80MHz

# blink - GPIO18
output:
  - platform: gpio
    pin: 18
    id: led_out
light:
  - platform: binary
    name: "LED"
    output: led_out
Find it: search ESPHome's board list for esp32dev (same ids as PlatformIO).
esptool doesn't pick board settings — a prebuilt .bin already has them baked in. This is just the raw flash command.
terminal Copy
esptool.py --chip esp32 --port /dev/ttyACM0 \
  --baud 921600 write_flash 0x0 firmware.bin
--port = your /dev/tty* (macOS/Linux) or COMx (Windows).
Build details: sketch space 1310720 B · data 327680 B · DIO

Specifications

ESP32 · 55 × 20 mm
Compute
MCU
ESP32
Clock
240 MHz
SRAM · Flash
520 KB · 4MB · 4MB (QSPI) PSRAM
Radio
Wi-Fi
802.11 b/g/n
Bluetooth
4.2 LE
Antenna
u.FL
I/O
GPIO · ADC
26 · 18
UART · I²C · SPI
3 · 2 · 4
PWM
16 channels
Power
USB
None
Serial
-
Boot address
0x1000
Flashing
Upload · OTA
esptool_py · esp_ota
Flash · Boot mode
DIO · DIO
Sketch · Data
1.25 MB · 320 KB
20 mm55 mm
55 × 20 mm
The LoPy4 uses esptool_py for firmware uploads, esp_ota for over-the-air (OTA) updates. Flash mode is DIO with DIO boot mode. The maximum sketch size is 1.25 MB with 320 KB available for data.

About this board

At its core is the ESP32 - a dual-core Xtensa with both Bluetooth Classic and BLE.

Expect to pay about $49.95 - above the ~$20 typical for ESP32 boards.

Onboard you'll find 4MB (QSPI) PSRAM and LoRa (SX1276).

  • Quadruple-network module: LoRa, Sigfox, Wi-Fi & BLE
  • Onboard ceramic antenna for Wi-Fi/BLE; u.FL connectors for LoRa & Sigfox
  • No onboard USB - needs Pycom Expansion Board, Pysense or Pytrack to connect

Where to buy

prices are typical street prices
LoPy4
LoPy4
$49.95per unit, typical

Resources

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