48-Pin GPIO Interface

The Rhino Pi-A1 features an onboard 2×24 PIN GPIO interface.

Warning

When using the 48-Pin GPIO interface, pay attention to the wiring between the pins and peripherals. Ensure correct pin connections—improper operation may cause damage to the device hardware.

48-Pin 3.3V GPIO Expansion Interface

The Rhino Pi-A1 is equipped with a 2×24 PIN interface, providing highly flexible interface support for hardware expansion. Users can connect various sensors, communication modules, displays, and other embedded peripherals via this interface to implement rapid prototyping and functional verification in fields such as the Internet of Things (IoT), robot control, and industrial automation.

The functions of the 48-Pin 3.3V GPIO expansion interface are shown in the table below:

Category	Interface	Description
Signal conversion	CAN interface	2x CAN FD
Signal conversion	RS485	1x RS485
Signal conversion	RS232	2x RS232
Signal conversion	Optocoupler	2x input, 2x output, interface voltage range 5~30V
Reserved signal interface	I2S	1x
Reserved signal interface	SPI	1x
Reserved signal interface	DEBUG UART	1x
Reserved signal interface	UART	1x
Reserved signal interface	GPIO	5x
Reserved signal interface	5V	1x
Reserved signal interface	3.3V	1x

Rhino Pi-A1 24×2 board pin definition table:

No.	Board Silkscreen	GPIO/System Mapping	Description
1	HDMI_OUT	OUT3.3V	3.3V voltage
2	5V	GPIO117	After pulling the pin level high, the pin outputs 5V voltage, restored after device restart
3	GND	GND	Ground
4	GND	GND	Ground
5	DBG_TX	DBG_TX	Debug-UART TX pin, used for system serial log input/output
6	DBG_RX	DBG_RX	Debug-UART RX pin, used for system serial log input/output
7	UART4_RX	UART4_RX	UART RX pin
8	UART4_TX	UART4_TX	UART TX pin
9	GPIO5/OUT	GPIO17	Corresponds to GPIO17, for GPIO expansion
10	GPIO199/OUT	GPIO148	Corresponds to GPIO148, for GPIO expansion
11	I2S0_SCK	I2S0_SCK	I2S audio bit clock, used for audio data synchronous transmission
12	SPI1_MISO	SPI1_MISO	SPI1 master-in slave-out, serial data receive channel
13	I2S0_WS	I2S0_WS	I2S audio frame synchronization, distinguishes left/right channel data
14	SPI1_MOSI	SPI1_MOSI	SPI1 master-out slave-in, serial data transmit channel
15	I2S0-DATA0	I2S0-DATA0	I2S audio data channel 0, transmits audio sample data
16	SPI1_CLK	SPI1_CLK	SPI1 serial clock, synchronizes bus data transmission
17	I2S0-DATA1	I2S0-DATA1	I2S audio data channel 1, transmits audio sample data
18	SPI1_CS_N	SPI1_CS_N	SPI1 chip select signal, active low, selects slave device
19	GND	GND	Ground
20	GND	GND	Ground
21	RS232_1_TX	RS232_1_TX	First RS232 serial transmit pin
22	RS232_1_RX	RS232_1_RX	First RS232 serial receive pin
23	OUT_GPIO40_INT	GPIO35	Corresponds to GPIO35, for GPIO expansion
24	OUT_GPIO87_INT	GPIO158	Corresponds to GPIO158, for GPIO expansion

Basic Interface Testing

GPIO

General-Purpose Input/Output (GPIO) refers to non-specialized digital signal pins on integrated circuits or electronic circuit boards (such as MCU/MPU). These pins can be used as input, output, or both, and are controllable via software.

Preparation

• Rhino Pi-A1
• Multimeter
• Open-source tool: gpiod

sudo apt update
sudo apt install gpiod libgpiod2 libgpiod-dev

Connection

Take the 5V PIN (GPIO117) of the Rhino Pi-A1 48 PIN as an example for testing:

• Turn on the multimeter and rotate the switch to the DC voltage 10V range gear.
• Connect the red multimeter lead to the 5V PIN (GPIO117) on the 48 PIN side of the Rhino Pi-A1.
• Connect the black multimeter lead to the GND PIN (GND) on the 48 PIN side of the Rhino Pi-A1.

Testing

• Output High Level

sudo gpioset /dev/gpiochip3 117=1

Observe that the multimeter shows a voltage of approximately 5V.

• Output Low Level

sudo gpioset /dev/gpiochip3 117=0

Observe that the multimeter shows a voltage of approximately 0V.

More Interface Applications

For more 48 PIN interface applications, please refer to 48 PIN Pin Applications.