VALTRACK V4 MFW ESP32 C3
ESP32-C3-based mobile field worker tracker - ideal for workforce monitoring and remote task logging.

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Pinout
13 pins| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 0 | TX1 | safe | - | |
| 2 | 1 | RX1 | safe | - | |
| 3 | 2 | A0D0GPIO_ANALOG_IN | strapping | adc | |
| 4 | 3 | A1D1GPIO_INT1 | safe | adc | |
| 5 | 4 | A2D2GPIO_TPS_ENABLEGPIO_CHG_IN | strapping | adc | |
| 6 | 5 | SDAA3D3GPIO_IIC_DATA | strapping | adc · i2c | |
| 7 | 6 | SCLD4GPIO_IIC_CLOCK | strapping | i2c | |
| 8 | 7 | D5GPIO_PWRKEY | strapping | - | |
| 9 | 8 | SCKD8GPIO_LED_SIGNAL | strapping | spi | |
| 10 | 9 | MISOD9GPIO_SOS | strapping | spi | |
| 11 | 10 | MOSID10GPIO_GSM_ENABLE | safe | spi | |
| 12 | 20 | RXSSD7 | uart | spi · uart | |
| 13 | 21 | TXD6 | uart | uart |
Start with these
4 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
sampled at boot or shared with debug/serial| Pin | Label | What to know | Role |
|---|---|---|---|
| A0 | GPIO2 | Must be held high during boot (if low on reset, normal flash boot may fail) | Strapping |
| A2 | MTMS | Used during boot; JTAG TMS for debugging; acts as Quad-SPI flash IO (hold data line) in internal-flash variants | JTAG |
| SDA | MTDI | Used during boot; JTAG TDI for debugging; acts as Quad-SPI flash IO (write-protect data line) in internal-flash variants | JTAG |
| SCL | MTCK | Used during boot; JTAG TCK for debugging; provides flash clock in internal-flash variants | JTAG |
| D5 | MTDO | Used during boot; JTAG TDO for debugging; acts as Quad-SPI flash IO (data line) in internal-flash variants | JTAG |
| SCK | GPIO8 | Must be held high during reset (if low, UART flashing/boot may not work) | Strapping |
| MISO | GPIO9 | Controls boot mode on reset (HIGH for normal flash boot, LOW enters serial download mode) | Strapping |
| RX | U0RXD | Used as UART0 receive (console/bootloader); repurposing may disable serial programming and debug logs | UART |
| TX | U0TXD | Used as UART0 transmit (console/bootloader); repurposing may disable serial console output and printing | UART |
Pinout notes All 13 pins on the VALTRACK V4 MFW ESP32 C3 are usable GPIO. Peripheral wiring is straightforward: I²C is mapped to SDA on GPIO5 and SCL on GPIO6; the SPI bus…
All 13 pins on the VALTRACK V4 MFW ESP32 C3 are usable GPIO.
Peripheral wiring is straightforward: I²C is mapped to SDA on GPIO5 and SCL on GPIO6; the SPI bus (MOSI, MISO, SCK, SS) is broken out in full; TX/RX on GPIO21 and GPIO20 cover serial logging and flashing.
Beyond plain digital I/O you get 4 ADC-capable pins for sensors and battery monitoring.
9 of the exposed pins carry boot-time or system duties on the ESP32-C3 (A0, A2, SDA and 6 more) - check the guidance above before wiring anything to them. TX1, RX1, A1 and MOSI are free of any such role - the safest first picks.
Getting started
flash your first firmware in ~2 minutesBoard: ESP32C3 Dev Module USB CDC On Boot: Enabled Flash Size: 4MB (32Mb) Flash Mode: QIO Partition Scheme: Default 4MB with spiffs (1.2MB APP / 1.5MB SPIFFS) Upload Speed: 921600
// blink the onboard LED
void setup() {
pinMode(0, OUTPUT);
}
void loop() {
digitalWrite(0, HIGH); delay(500);
digitalWrite(0, LOW); delay(500);
}[env:VALTRACK_V4_MFW_ESP32_C3]
platform = espressif32
board = esp32-c3-devkitm-1
framework = arduino
monitor_speed = 115200
upload_speed = 921600esp32-c3-devkitm-1 — or type it after board =.esp32:
board: esp32-c3-devkitm-1
variant: VALTRACK_V4_MFW_ESP32_C3
framework:
type: esp-idf
# blink - GPIO0
output:
- platform: gpio
pin: 0
id: led_out
light:
- platform: binary
name: "LED"
output: led_outesp32-c3-devkitm-1 (same ids as PlatformIO).esptool.py --chip esp32c3 --port /dev/ttyACM0 \
--baud 921600 write_flash 0x0 firmware.bin--port = your /dev/tty* (macOS/Linux) or COMx (Windows).Specifications
ESP32-C3 · 58.2 × 30 mmAbout this board
Inside sits the ESP32-C3 - a single-core RISC-V and the budget low-power pick.
At $59.00 it's on the expensive side for an ESP32-C3 board - most land around $10.
Around the module: GPS, a motion sensor (LIS3DH), cellular connectivity (SIMCom A7672S), battery charging (TP4056) and status LEDs (Battery, Cellular, GPS).
It flashes over native USB - no serial-converter driver needed, which isn't a given among ESP32-C3 boards.
- 4G-LTE Cat-1 with 2G fallback plus inbuilt GNSS
- Modem variants: A7672S/E/SA or SIM7672G by region
- Movement-triggered GPS reporting via LIS3DH
- HTTP / MQTT / SMS protocols; BLE setup app
- Optional IP67 enclosure; onboard patch or external U.FL antenna
Where to buy
prices are typical street prices
Resources
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