Pinout Reference

Pin Map Overview

Note

The pin assignments follow the ESP32-S3 GPIO numbering scheme. Color coding: Red = Power, Green = GND, Blue = GPIO, Pink = ADC/DAC, Yellow = Serial/SPI/I2C, Purple = Connected internally.

Header J2 (Left Side)

Power Pins

Pin	Name	Type	Function
1	5V	Power	5V power supply
2	GND	Power	Ground
3	3V3	Power	3.3V output
4	GND	Power	Ground
5	3V3	Power	3.3V output
6	GND	Power	Ground
7	Vext	Power	3.3V output for TFT and GNSS
8	GND	Power	Ground

GPIO Pins (J2)

Pin	GPIO	Type	Primary Function	Alternate Functions
1	RST	-	Reset button	-
2	0	I/O	USER button	Boot select
3	1	I/O	Vbat_Read¹	Touch1, ADC1_CH0
4	2	I/O	ADC Control	Touch2, ADC1_CH1
5	3	I/O	Vext Control²	Touch3, ADC1_CH2
6	19	I/O	USB D-	CLK_OUT2, ADC2_CH8, U1RTS
7	20	I	USB D+	CLK_OUT1, ADC2_CH9, U1CTS
8	21	I/O	TFT backlight	-
9	26	I/O	General I/O	SPICS1
10	48	I/O	D_SEL	-
11	47	I/O	Boot mode	-
12	33	I/O	GNSS TX	SPIIO4, FSPIHD
13	34	I/O	GNSS RX	SPI05, FSPICS0
14	35	I/O	GNSS RST	SPI06, FSPID
15	36	I/O	GNSS PPS	SPI07, FSPICLK
16	37	I/O	General I/O	SPIDQS, FSPIQ

Battery Reading

¹ Battery voltage: VBAT = Vbat_Read × 4.9

V1.1 Hardware

² GPIO3 controls GNSS power on V1.1. Set HIGH to enable the GNSS module.

Header J3 (Right Side)

GPIO Pins (J3)

Pin	GPIO	Type	Primary Function	Alternate Functions
1	18	I/O	LED Control	U1RXD, ADC2_CH7, CLK_OUT3
2	17	I/O	General I/O	U1TXD, ADC2_CH6
3	16	I/O	General I/O	U0CTS, ADC2_CH5, XTAL_32K_N
4	15	I/O	General I/O	U0RTS, ADC2_CH4, XTAL_32K_P
5	7	I/O	General I/O	ADC1_CH6, Touch7
6	6	I/O	General I/O	ADC1_CH5, Touch6
7	5	I/O	General I/O	ADC1_CH4, Touch5
8	4	I/O	General I/O	ADC1_CH3, Touch4

Pin	GPIO	Type	Primary Function	Alternate Functions
1	46	I/O	I2C SCL	-
2	45	I/O	I2C SDA	-
4	44	I/O	U0RXD	Serial RX
5	43	I/O	U0TXD	Serial TX
6	14	I/O	LoRa DIO1	ADC2_CH3, Touch14
7	13	I/O	LoRa Busy	ADC2_CH2, Touch13
8	12	I/O	LoRa RST	ADC2_CH1, Touch12
9	11	I/O	LoRa MISO	ADC2_CH0, Touch11
10	10	I/O	LoRa MOSI	ADC1_CH9, Touch10
11	9	I/O	LoRa SCK	ADC1_CH8, Touch9
12	8	I/O	LoRa NSS	ADC1_CH7, Touch8, SUBSPICS1
13	42	I/O	TFT SDIN	MTMS
14	41	I/O	TFT SCLK	MTDI
15	40	I/O	TFT RS	MTMS
16	39	I/O	TFT RES	MTMS
18	38	I/O	TFT CS	FSPIWP, SUBSPIWP

Peripheral Pin Assignments

GNSS Module (UC6580)

Function	GPIO	Notes
TX	33	GNSS → ESP32
RX	34	ESP32 → GNSS
RST	35	Active low reset
PPS	36	1PPS timing output
Power	3	V1.1: HIGH to enable

LoRa Module (SX1262)

Function	GPIO	Notes
MOSI	10	SPI data out
MISO	11	SPI data in
SCK	9	SPI clock
NSS	8	Chip select (active low)
RST	12	Reset
BUSY	13	Busy indicator
DIO1	14	Interrupt

TFT Display (ST7735S)

Function	GPIO	Notes
SDIN	42	SPI data
SCLK	41	SPI clock
RS (DC)	40	Data/Command
RES	39	Reset
CS	38	Chip select
LED_K	21	Backlight control

I2C Bus

Function	GPIO	Notes
SDA	45	Data
SCL	46	Clock

Tip

GPIO45 and GPIO46 are recommended for external I2C devices as they don’t conflict with built-in peripherals.

Code Examples

Pin Definitions

// Wireless Tracker Pin Definitions

// GNSS (UC6580)
#define GNSS_TX_PIN     33
#define GNSS_RX_PIN     34
#define GNSS_RST_PIN    35
#define GNSS_PPS_PIN    36
#define GNSS_PWR_PIN    3    // V1.1 only

// LoRa (SX1262)
#define LORA_MOSI_PIN   10
#define LORA_MISO_PIN   11
#define LORA_SCK_PIN    9
#define LORA_NSS_PIN    8
#define LORA_RST_PIN    12
#define LORA_BUSY_PIN   13
#define LORA_DIO1_PIN   14

// TFT Display
#define TFT_SDIN_PIN    42
#define TFT_SCLK_PIN    41
#define TFT_DC_PIN      40
#define TFT_RST_PIN     39
#define TFT_CS_PIN      38
#define TFT_LED_PIN     21

// I2C
#define I2C_SDA_PIN     45
#define I2C_SCL_PIN     46

// User Interface
#define USER_BTN_PIN    0
#define LED_PIN         18

// Battery
#define VBAT_ADC_PIN    1
#define VBAT_ADC_CTRL   2
#define VEXT_CTRL_PIN   3

Initialization

void initGNSS() {
    // Enable GNSS power (V1.1)
    pinMode(GNSS_PWR_PIN, OUTPUT);
    digitalWrite(GNSS_PWR_PIN, HIGH);

    // Setup GNSS serial
    Serial1.begin(115200, SERIAL_8N1, GNSS_RX_PIN, GNSS_TX_PIN);
}

void initLoRa() {
    SPI.begin(LORA_SCK_PIN, LORA_MISO_PIN, LORA_MOSI_PIN, LORA_NSS_PIN);

    pinMode(LORA_RST_PIN, OUTPUT);
    pinMode(LORA_BUSY_PIN, INPUT);
    pinMode(LORA_DIO1_PIN, INPUT);

    // Reset LoRa module
    digitalWrite(LORA_RST_PIN, LOW);
    delay(10);
    digitalWrite(LORA_RST_PIN, HIGH);
    delay(10);
}

void initDisplay() {
    pinMode(TFT_LED_PIN, OUTPUT);
    digitalWrite(TFT_LED_PIN, HIGH);  // Enable backlight

    // TFT initialization via library...
}

float readBatteryVoltage() {
    pinMode(VBAT_ADC_CTRL, OUTPUT);
    digitalWrite(VBAT_ADC_CTRL, LOW);

    int raw = analogRead(VBAT_ADC_PIN);
    float voltage = (raw / 4095.0) * 3.3 * 4.9;

    digitalWrite(VBAT_ADC_CTRL, HIGH);
    return voltage;
}