Hardware interface description

Interface overview

• Radxa ZERO 3W

• Radxa ZERO 3E

Power

Debug Serial Port

Ethernet Port

40 PIN GPIO

GPIO voltage

GPIO	Voltage	Maximum
All GPIOs	3.3V	3.63V
SARADC_IN5	3.3V	3.3V

GPIO interface

Radxa ZERO 3 provides a 40-pin GPIO header, which is compatible with most SBC accessories on the market.

**Tips: Actual compatibility is based on usage **

tip

Pin 3, Pin 5, Pin 27, and Pin 28 add extra pull-up resistors for I2C device power supply, so they work abnormally when used as GPIOs.

GPIO number	Function5	Function4	Function3	Function2	Function1	Pin#	Pin#	Function1	Function2	Function3	Function4	Function5	GPIO number
					+3.3V	1	2	+5.0V
32				UART3_RX_M0	GPIO1_A0	3	4	+5.0V
33				UART3_TX_M0	GPIO1_A1	5	6	GND
116		PWM14_M0			GPIO3_C4	7	8	GPIO0_D1	UART2_TX_M0				25
					GND	9	10	GPIO0_D0	UART2_RX_M0				24
97					GPIO3_A1	11	12	GPIO3_A3				I2S3_SCLK_M0	99
98		I2S3_MCLK_M0			GPIO3_A2	13	14	GND
104					GPIO3_B0	15	16	GPIO3_B1	UART4_RX_M1	PWM8_M0			105
					+3.3V	17	18	GPIO3_B2	UART4_TX_M1	PWM9_M0			106
147		PWM15_IR_M1	I2S3_SCLK_M1	SPI3_MOSI_M1	GPIO4_C3	19	20	GND
149	UART9_TX_M1	PWM12_M1	I2S3_SDO_M1	SPI3_MISO_M1	GPIO4_C5	21	22	GPIO3_C1				I2S1_SDO2_M2	113
146		PWM14_M1	I2S3_MCLK_M1	SPI3_CLK_M1	GPIO4_C2	23	24	GPIO4_C6	SPI3_CS0_M1	PWM13_M1	UART9_RX_M1	I2S3_SDI_M1	150
					GND	25	26	NC
138		I2C4_SDA_M0	I2S2_SDI_M1		GPIO4_B2	27	28	GPIO4_B3			I2C4_SCL_M0	I2S2_SDO_M1	139
107					GPIO3_B3	29	30	GND
108					GPIO3_B4	31	32	GPIO3_C2	UART5_TX_M1			I2S1_SDO3_M2	114
115	UART5_RX_M1		I2S1_SCLK_RX_M2		GPIO3_C3	33	34	GND
100			I2S3_LRCK_M0		GPIO3_A4	35	36	GPIO3_A7					103
36			I2S1_SCLK_RX_M0		GPIO1_A4	37	38	GPIO3_A6				I2S3_SDI_M0	102
					GND	39	40	GPIO3_A5				I2S3_SDO_M0	101

USB Function Configuration on 40-Pin

On the ZERO 3W / 3E's 40-Pin interface, the following pins can be configured for USB 2.0:

• USB2_HOST2_DM: Pin number 28, resistor location R46.
• USB2_HOST2_DP: Pin number 27, resistor location R45.

By default, Pin-27 can be configured in software for functions such as GPIO4_B2 (see 40-Pin Pinout), while the USB2_HOST2_DP signal is not activated on the hardware. Pin-28 can be configured in software for functions such as GPIO4_B3 (see 40-Pin Pinout), and the USB2_HOST2_DM signal is also not activated on the hardware. To change these pins to USB functions, please follow the steps below to modify the reserved resistors:

• Remove the 0-ohm resistors at R32 and R39.
• Solder 0-ohm resistors at R45 and R46.

tip

The schematic and resistor locations can be viewed and downloaded from the hardware documentation.Hardware Documentation Download

[Operation Note]

This procedure requires soldering skills, and it is recommended that it be performed by an experienced technician.

USB C

There are two USB TYPE-C ports, one is USB 2.0 OTG port and the other is USB3.0 HOST port. The power supply is USB 2.0 OTG port.

HDMI

Provides a Micro HDMI port.

MIPI CSI

PIN	Name
1	GND
2	MIPI_CSI_RX_D0N
3	MIPI_CSI_RX_D0P
4	GND
5	MIPI_CSI_RX_D1N
6	MIPI_CSI_RX_D1P
7	GND
8	MIPI_CSI_RX_CLK0N
9	MIPI_CSI_RX_CLK0P
10	GND
11	MIPI_CSI_RX_D2N
12	MIPI_CSI_RX_D2P
13	GND
14	MIPI_CSI_RX_D3N
15	MIPI_CSI_RX_D3P
16	GND
17	CAMERAB_PDN_L
18	CIF_CLKOUT
19	GND
20	I2C2_SCL_M1
21	I2C2_SDA_M1
22	VCC_3V3