Trueverit ESP32 Universal IoT Driver MK II

by Trueverit

Enhanced version of the original driver board - supports advanced control features and secure updates.

Pinout

ESP32

MCU

240MHz

clock

4MB

flash

520KB

SRAM

18· 6 ADC

GPIO

BLE 4.2+ WiFi

radio

Pinout

18 pins

View:

Pin	GPIO	Labels	Status	Capabilities
1	1	TXETH_PHY_ADDRPWM	uart	uart
2	2	T2ETH_PHY_POWERPWM	strapping	touch
3	3	RXPWM	uart	uart
4	4	SCLT0PWM	strapping	touch · i2c
5	5	SSPWM	strapping	spi
6	12	TX1PWM	strapping	-
7	13	RX1PWM	strapping	-
8	14	ETH_PHY_MDIOPWM	strapping	-
9	15	SDAPWM	strapping	i2c
10	16	ETH_PHY_MDCPWM	strapping	-
11	18	LED_BUILTINSCKPWM	safe	spi
12	23	MOSIPWM	safe	spi
13	32	MISOA4T9PWM	safe	adc · touch · spi
14	33	TX2A5T8PWM	safe	adc · touch
15	34	A6	strapping	adc
16	35	A7	strapping	adc
17	36	A0	strapping	adc
18	39	RX2A3	strapping	adc

Start with these

4 pins with no boot or system involvement

LED_BUILTINSCKMOSIPWMMISOA4TX2A5

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

Pin	Label	What to know	Role
T2	GPIO2	If driven HIGH on reset (while IO0 is LOW), selects an unsupported SDIO boot mode, causing boot failure.	Strapping
SCL	GPIO4	Sampled at reset for boot config; should not be driven at boot (affects boot mode timing).	Strapping
SS	GPIO5	Must be HIGH during boot; if pulled LOW at reset, alters SDIO slave timing and may prevent normal boot.	Strapping
TX1	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
RX1	MTCK (GPIO13)	Used for JTAG debugging (TCK); avoid using as GPIO if JTAG is needed.	Other
ETH_PHY_MDIO	MTMS (GPIO14)	Used for JTAG debugging (TMS); driving it as GPIO may interfere with JTAG or produce spurious signals at boot.	Other
SDA	MTDO (GPIO15)	Keep HIGH during boot (internal PU); if LOW on reset, bootloader log is silenced and boot mode may change.	Strapping
A6	GPIO34	Cannot be used as output (no drive capability); only suitable for analog/digital input.	Other
A7	GPIO35	Cannot be used as output; only suitable for input.	Other
A0	GPIO36 (SENSOR_VP)	Cannot be used as output; only suitable for input (e.g., analog read).	Other
RX2	GPIO39 (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

Pin	Label	What to know	Role
TX	U0TXD (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
RX	U0RXD (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
ETH_PHY_MDC	GPIO16	Connected to internal PSRAM on PSRAM-enabled modules; not usable as GPIO on those modules.	Flash

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 All 18 pins on the Trueverit ESP32 Universal IoT Driver MK II are usable GPIO. Peripheral wiring is straightforward: I²C is mapped to SDA on GPIO15 and SCL on…

All 18 pins on the Trueverit ESP32 Universal IoT Driver MK II are usable GPIO.

Peripheral wiring is straightforward: I²C is mapped to SDA on GPIO15 and SCL on GPIO4; the SPI bus (MOSI, MISO, SCK, SS) is broken out in full; TX/RX on GPIO1 and GPIO3 cover serial logging and flashing.

Beyond plain digital I/O you get 6 ADC-capable pins for sensors and battery monitoring and 4 capacitive-touch inputs.

11 of the exposed pins carry boot-time or system duties on the ESP32 (T2, SCL, SS and 8 more) - check the guidance above before wiring anything to them. LED_BUILTIN, MOSI, MISO and TX2 are free of any such role - the safest first picks.

Getting started

flash your first firmware in ~2 minutes

Tool:

Connect over USB

Install your USB-serial driver (CH340 / CP210x) if no port appears. Not detected? Hold BOOT while plugging in.

Match & flash

Set the Tools options shown, then click Upload.

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 Dev Module"▸

Flash Size: "4MB (32Mb)"▸

Flash Mode: "DIO"▸

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 Dev Module
Flash Size: 4MB (32Mb)
Flash Mode: DIO
Partition Scheme: Default 4MB with spiffs (1.2MB APP / 1.5MB SPIFFS)
Upload Speed: 921600

Find it: Tools ▸ Board ▸ ESP32 Arduino ▸ ESP32 Dev 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:esp32-trueverit-iot-driver-mkii]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
upload_speed = 921600

Find it: PlatformIO Home ▸ Boards, search esp32dev — or type it after board =.

board to selectesp32dev⧉ copy

device.yaml Copy

esp32:
  board: esp32dev
  variant: esp32-trueverit-iot-driver-mkii
  framework:
    type: esp-idf

# 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

Compute

MCU

ESP32

Clock

240 MHz

SRAM · Flash

520 KB · 4MB

Radio

Wi-Fi

802.11 b/g/n

Bluetooth

4.2 LE

Antenna

PCB

I/O

GPIO · ADC

18 · 6

UART · I²C · SPI

3 · 2 · 4

PWM

16 channels

Power

USB

Serial

Boot address

0x1000

Flashing

Upload · OTA

esptool_py · esp_ota

Flash · Boot mode

DIO · DIO

Sketch · Data

1.25 MB · 320 KB

The Trueverit ESP32 Universal IoT Driver MK II 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

Inside sits the ESP32 - a dual-core Xtensa with both Bluetooth Classic and BLE.

Only 18 GPIO are broken out, where most ESP32 boards manage about 24 - worth checking the pinout covers what you need.

Around the module: wired Ethernet (DP83848).

Resources

ESP32 datasheet espressif.com↗ Trueverit Universal IoT Driver (manufacturer) trueverit.com↗PlatformIO board definition docs.platformio.org↗arduino-esp32 variant (pins_arduino.h) github.com↗

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