RK3576 interface usage

Internal Low-speed Control Interface

GPIO/LED

Function Overview
RK3576 features a total of xxx GPIOs, most of which are allocated to other functions (e.g., I2C, UART, etc.). To use these interfaces as general-purpose GPIOs, their functional assignments must be released in the device tree.
The RK3576 carrier board is equipped with a green LED (USER) for customizing light status, which uses the GPIO4_C7 pin (GPIO ID: 151).

GPIO ID Calculation Method

GPIO ID = 32*X + 8*Y + Z

Example: GPIO4_C7
X=4, Y=2(C), Z=7
GPIO ID = 32*4+8*2+7 = 151

Command Line Related Commands

# cat /sys/class/gpio/gpio151/direction # Read the operation direction
# echo out > /sys/class/gpio/gpio151/direction # Set as output
# echo in > /sys/class/gpio/gpio151/direction # Set as input
# echo in > /sys/class/gpio/gpio151/direction # Set to input mode
# cat /sys/class/gpio/gpio151/value # Read the current level status
# echo 0 >/sys/class/gpio/gpio151/value # Output low level
# echo 1 >/sys/class/gpio/gpio151/value # Output high level
# echo 151 > /sys/class/gpio/export # Export the GPIO interface

Test Script
This script is located at /dfrobot-test/blink.sh. Please execute it with root privileges, and you will see the LED on the carrier board blink at one-second intervals.

# . /dfrobot-test/blink.sh`

Script Code

#!/bin/bash

GPIO=151

cleanup() {
    echo 0 > /sys/class/gpio/gpio${GPIO}/value
    echo ${GPIO} > /sys/class/gpio/unexport 
    exit 0
}

trap cleanup EXIT

echo ${GPIO} > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio${GPIO}/direction


while true; do
    echo 1 > /sys/class/gpio/gpio${GPIO}/value
    sleep 1
    echo 0 > /sys/class/gpio/gpio${GPIO}/value
    sleep 1
done

I2C/RTC

Function Overview
RK3576 is equipped with 10 I2C ports, some of which are multiplexed with other functions.

• Supports 7-bit and 10-bit address modes
• Software-programmable clock frequency
• Supports 100 kbps standard mode and 400 kbps fast mode

The usage of I2C ports on the RK3576 carrier board is as follows:

Command Line Related Commands
The RK3576 carrier board is equipped with an on-board RTC chip – IT8563UE

# cat /sys/class/rtc/rtc0/date     # Get the RTC date
# cat /sys/class/rtc/rtc0/time     # Get the RTC time
# cat /proc/driver/rtc             # Print RTC-related information

The output after executing the command is as follows:

UART

The RK3576 has 12 UART ports, some of which are multiplexed with other functions.

• Integrates two 64-byte FIFOs
• Supports 5-bit, 6-bit, 7-bit, and 8-bit serial data reception
• Supports standard asynchronous communication
• Supports various input clocks, with baud rates up to 8 Mbps
• UART1 to UART11 support automatic flow control mode
• UART1 to UART11 support RS485 function

The UART usage of the RK3576 carrier board is as follows:

Fan Control

Built-in fan control interface. Usage is as follows:

linaro@linaro-alip:~$ dfrobot-fan-ctl --help
Device found: hwmon6 (name: 'dfrobot-fan')
Fan device found: /sys/class/hwmon/hwmon6
DFRobot Fan Control Program
Usage: dfrobot-fan-ctl [options]

Options:
  -t, --temp          Show current temperature
  -f, --fan           Show fan status
  -s, --status        Show all status information
  --set-temp <value>  Set temperature threshold (°C, range 0.0-100.0)
  --set-time <value>  Set check interval (seconds, range 1.0-60.0)
  --monitor           Enter monitor mode
  -h, --help          Show this help message

Examples:
  dfrobot-fan-ctl -s                    # Show all status
  dfrobot-fan-ctl --set-temp 65.5       # Set temperature threshold to 65.5°C
  dfrobot-fan-ctl --set-time 2.5        # Set check interval to 2.5 seconds
  dfrobot-fan-ctl --monitor             # Enter monitor mode
linaro@linaro-alip:~$ dfrobot-fan-ctl -s
Device found: hwmon6 (name: 'dfrobot-fan')
Fan device found: /sys/class/hwmon/hwmon6
Current temperature: 36.1°C (36076 millidegree)
Fan status: OFF
Temperature threshold: 60.0°C (60000 millidegree)
Check interval: 10.0 seconds (10000 milliseconds)

Please note that root privileges are required when setting the fan temperature threshold and query time.

linaro@linaro-alip:~$ dfrobot-fan-ctl --set-temp 65.5
Device found: hwmon6 (name: 'dfrobot-fan')
Fan device found: /sys/class/hwmon/hwmon6
Failed to set temperature threshold: Permission denied
linaro@linaro-alip:~$ sudo dfrobot-fan-ctl --set-temp 65.5
Device found: hwmon6 (name: 'dfrobot-fan')
Fan device found: /sys/class/hwmon/hwmon6
Temperature threshold set: 65.5°C (driver value: 65500 millidegree)

Industrial and Serial Communication Interfaces

RS485

To test RS485 transmission and reception, a USB-to-RS485 adapter is required. Before use, connect RS485_A on the RK3576 carrier board to the RS485_A port of the USB-to-RS485 adapter, and RS485_B on the RK3576 carrier board to the RS485_B port of the adapter.

RS485 on the RK3576 carrier board is mapped to UART7.

Command Line Operations for RS485-related Commands

# Configure RS485 communication parameters
# stty -F /dev/ttyS7 115200 cs8 -parenb -cstopb

# Send data
# echo "hello dfrobot" > /dev/ttyS7

# Receive data
# cat /dev/ttyS7

CAN

The RK3576 has 2 CAN ports.

• Compliant with CAN and CAN FD specifications
• Supports standard and extended CAN frames
• Supports data frames, remote frames, overload frames, error frames, and interframe space
• Supports an 8192-bit receive FIFO

The RK3576 carrier board exposes 2 CAN channels.

Command Line Operations for CAN-related Commands

# Disable CAN device
# ip link set can1 down

# Enable CAN device
# ip link set can0 up

# Configure CAN communication parameters
# ip link set can1 type can bitrate 500000 dbitrate 2000000 sample-point 0.8 fd on
# Parameter Description
# bitrate      Set baud rate to
# dbitrate     Set data baud rate
# sample-point Set sample point position
# fd on        Whether to enable CAN-FD

# View CAN network interface
# ifconfig can0

# Optional: Configure "TX queue length" to optimize the send queue buffer size. 
# This setting can significantly reduce frame loss when a large number of high-speed frames need to be sent (e.g., CAN-FD).
# echo 4096 > /sys/class/net/can1/tx_queue_len

# Send data              
# cansend can1 5A1#123456

# Receive data                           
# candump can0

Using CAN
To ensure the security of the CAN bus, the system disables the SocketCAN interface by default. You need to configure and enable it using the ip link set ... command.

1. Configure and enable CAN

   # ip link set can0 type can bitrate 500000 dbitrate 2000000 sample-point 0.8 fd on
   # ip link set can0 up
   

2. View enabled CAN ports

   # ifconfig can0
   

3. Send data

   # cansend can0 5A1#123456
   

Audio and Video Interfaces

Display Output Interfaces

RK3576 supports display output via HDMI, eDP, DP, MIPI-DSI, EBC, and parallel interfaces.

• HDMI/eDP TX Interface

  • HDMI Interface
    • HDMI V2.1
    • Up to 4K@120Hz
    • Output data formats: RGB/YUV444/YUV422/YUV420, 8/10-bit
  • eDP Interface
    • eDP V1.3, compatible with DisplayPort V1.2
    • Up to 4K@60Hz
    • Output data formats: RGB/YUV444/YUV422, 8/10-bit

• DP V1.4 TX Interface

  • Supports DisplayPort V1.4
  • Up to 4K@120Hz
  • Output data formats: RGB/YUV444/YUV422/YUV420, 8/10-bit

• MIPI DSI-2 TX Interface

  • MIPI DSI-2 V1.1 interface with D-PHY V2.0 or C-PHY V1.1
  • Supports D-PHY 4 data lanes or C-PHY 3 data trios
  • Up to 2560×1600@60Hz
  • Supports up to 10-bit RGB data format

• EBC Interface

  • Supports E-ink EPD
  • Supports 2560×1920 hardware decoding
  • Supports 16-bit data bus
  • Supports 32 grayscale levels

• Parallel Interface

  • Supports RGB/BT656/BT1120
  • Up to 1920×1080@60Hz
  • Supports up to 8-bit RGB data format

The RK3576 video output processor features three video output ports
(HDMI/eDP/DP/DSI-2 can be connected to any Video Port; the parallel output interface can only be connected to Video Port 1 or 2).

• Video Port0: Supports up to 10-bit 4K@120Hz video
• Video Port1: Supports up to 10-bit 2560×1600@60Hz video
• Video Port2: Supports up to 8-bit 1920×1080@60Hz video

The RK3576 carrier board leads out standard HDMI (Type-A), DP, and DSI interfaces.
The default video output port assignment is as follows:

• Video Port0: HDMI Interface, max. 4K@120Hz
• Video Port1: DSI Interface, max. 2560×1600@60Hz
• Video Port2: DP Interface, max. 1920×1080@60Hz

Video Input Interfaces

The RK3576 supports video input via MIPI-CSI and DVP interfaces.

• MIPI-CSI Interface

  • Supports 5 CSI-2 interfaces
  • Port 0 supports 4 D-PHY data lanes or 3 C-PHY trios
  • Ports 1–4 support 2 D-PHY V1.2 data lanes (2.5 Gbps/lane); two ports can be combined into one port with 2 data lanes after merging

• DVP Interface

  • Supports 8/10/12/16-bit, 150 MHz I/O frequency
  • Supports BT.601/BT.656 and BT.1120 VI interfaces

The RK3576 carrier board exposes 3 MIPI-CSI interfaces, each with 4 data lanes:

• CAM0: Uses CSI0 port, with I2C6
• CAM1: Uses CSI1 and CSI2 ports, with I2C5
• CAM2: Uses CSI3 and CSI4 ports, with I2C8

Currently, the RK3576 has been adapted to the IMX415 camera.

Command-line operations for CSI-related commands

# Check camera devices and find the corresponding device in rkisp_mainpath
# v4l2-ctl --list-devices

# Preview the camera; the format, resolution, and frame rate can be modified according to actual conditions
# gst-launch-1.0 v4l2src device=/dev/video11 ! video/x-raw,format=NV12,width=3840,height=2160,framerate=30/1 ! videoconvert ! autovideosink

Audio

The RK3576 supports 5 Serial Audio Interfaces (SAI).

• SAI0/1 support 4 TX channels and 4 RX channels
• SAI2/3/4 support 1 TX channel and 1 RX channel
• Supports I2S/TDM/PCM modes
• Supports 3 I2S formats
• Supports 4 PCM formats
• Sampling rate up to 192 kHz
• Supports audio resolution from 16 to 32 bits

The RK3576 carrier board is equipped with the ES8388 audio codec chip.
It uses SAI1 for audio transmission and I2C3 for configuration and control.

• The MIC jack is connected to the IN2 interface of the ES8388.
• The SPK is connected to the OUT1 interface of the ES8388 via an amplifier chip (PAM8302AADCR).
• The PHONE jack is connected to the IN1 and OUT2 interfaces of the ES8388.

Test Script
This script is located at /dfrobot-test/audio.sh. Short-circuit the TX and RX pins of UART3, then execute the script with root privileges to view the test results.

# Test SPK and MIC
# . /dfrobot-test/audio.sh speaker

# Test PHONE audio
# . /dfrobot-test/audio.sh headphone

Script Code

#!/bin/bash

# Sound card test script
# Supports two modes: speaker test (default) and headphone test
# Usage: 
#   ./audio.sh speaker   # Test speaker and main microphone
#   ./audio.sh headphone # Test headphone and headphone microphone

# Function: Configure speaker mode
setup_speaker_mode() {
    # SAI interface configuration
    amixer -c 0 cset numid=31,iface=MIXER,name='SAI1 Transmit SDO2 Source Select' 0
    amixer -c 0 cset numid=4,iface=MIXER,name='SAI1 Receive SDIx Select' 1
    amixer -c 0 cset numid=3,iface=MIXER,name='SAI1 Transmit SDOx Select' 1
    
    # Output channel configuration
    amixer -c 0 cset name='OUT1 Switch' on
    amixer -c 0 cset name='OUT2 Switch' off
    amixer -c 0 cset name='spk switch' on
    amixer -c 0 cset name='Speaker Switch' on
    amixer -c 0 cset name='Headphone Switch' off
    
    # Input channel configuration
    amixer -c 0 cset name='Main Mic Switch' on
    amixer -c 0 cset name='Headset Mic Switch' off
    
    # PGA mixer configuration
    amixer -c 0 cset name='Left PGA Mux' 1
    amixer -c 0 cset name='Right PGA Mux' 1
    
    echo "Configured to speaker mode"
}

# Function: Configure headphone mode
setup_headphone_mode() {
    # SAI interface configuration
    amixer -c 0 cset numid=31,iface=MIXER,name='SAI1 Transmit SDO2 Source Select' 0
    amixer -c 0 cset numid=4,iface=MIXER,name='SAI1 Receive SDIx Select' 1
    amixer -c 0 cset numid=3,iface=MIXER,name='SAI1 Transmit SDOx Select' 1
    
    # Output channel configuration
    amixer -c 0 cset name='OUT1 Switch' off
    amixer -c 0 cset name='OUT2 Switch' on
    amixer -c 0 cset name='spk switch' off
    amixer -c 0 cset name='Speaker Switch' off
    amixer -c 0 cset name='Headphone Switch' on
    
    # Input channel configuration
    amixer -c 0 cset name='Main Mic Switch' off
    amixer -c 0 cset name='Headset Mic Switch' on
    
    # PGA mixer configuration (Note: Use 0 for headphone mode)
    amixer -c 0 cset name='Left PGA Mux' 0
    amixer -c 0 cset name='Right PGA Mux' 0
    
    echo "Configured to headphone mode"
}

# Display current audio device information
show_audio_devices() {
    echo "================================================"
    echo "System audio device list:"
    echo "Playback devices:"
    aplay -l
    echo "Recording devices:"
    arecord -l
    echo "================================================"
}

# Main program starts
show_audio_devices

# Parse command line arguments
MODE=${1:-speaker}  # Default to speaker mode

case $MODE in
    speaker|spk)
        setup_speaker_mode
        DEVICE_NAME="Speaker"
        MIC_NAME="Main Microphone"
        ;;
    headphone|hp)
        setup_headphone_mode
        DEVICE_NAME="Headphone"
        MIC_NAME="Headset Microphone"
        ;;
    *)
        echo "Error: Unknown mode '$MODE'"
        echo "Available modes: speaker, headphone"
        exit 1
        ;;
esac

# Execute real-time recording and playback test
echo "Starting test: Playback via ${DEVICE_NAME}, Recording via ${MIC_NAME}"
echo "================================================"
echo "Test instructions:"
echo "1. Please speak into the ${MIC_NAME}"
echo "2. Sound will be played back in real-time via ${DEVICE_NAME}"
echo "3. Press CTRL+C to stop the test"
echo "================================================"

# Set trap to ensure audio stream is closed on exit
trap 'echo "Test stopped"; exit 0' SIGINT

# Execute real-time recording and playback (CD quality: 44.1kHz, 16-bit, stereo)
arecord -v -f cd -Dhw:0 | aplay -v -Dhw:0 -f cd

# Handle potential errors
if [ $? -ne 0 ]; then
    echo "Error: Audio device operation failed! Please check:"
    echo "1. Whether the sound card device exists (hw:0)"
    echo "2. Whether you have access permissions to audio devices"
    echo "3. Whether other processes are occupying the audio device"
    echo "4. Whether physical connections are correct (microphone and headphone are plugged in)"
    exit 1
fi

Network Communication Interfaces

Ethernet

The RK3576 supports two Ethernet controllers, compliant with IEEE 802.3 10/100/1000 Mbps, with RGMII and RMII interfaces.
The RK3576 carrier board provides two 1000M Ethernet ports.

Related Command-Line Instructions

# Install bandwidth test tool
# sudo apt install iperf3

# Test network performance
# iperf3 -c 192.168.199.129 -p 5011

WiFi/Bluetooth

The RK3576 carrier board integrates an AP6256 (2.4G/5G WiFi + Bluetooth 5) module.
The module is connected to the RK3576 via SDIO1, and uses UART4 for Bluetooth data transmission.

Related Command-Line Instructions

# Scan available Wi-Fi networks
# nmcli device wifi list

# Connect to Wi-Fi
# nmcli device wifi connect <SSID> password <password>

# Connect using a specific network interface
# nmcli device wifi connect <SSID> password <password> ifname wlan0

# Disconnect Wi-Fi
# nmcli device disconnect wlan0

Related Command-Line Instructions
In Linux systems, Bluetooth management is primarily implemented via the bluetoothctl command-line tool.

1. Startup and Status Check

   bluetoothctl                 # Enter interactive mode
   [bluetooth]# show            # Display controller status
   [bluetooth]# list            # List available controllers
   [bluetooth]# power on        # Turn on Bluetooth
   [bluetooth]# power off       # Turn off Bluetooth
   

2. Device Scanning and Management

   [bluetooth]# scan on         # Start scanning for devices
   [bluetooth]# scan off        # Stop scanning
   [bluetooth]# devices         # List discovered devices
   

3. Pair Devices

   [bluetooth]# pair 00:11:22:AA:BB:CC  # Pair using the device MAC address
   # The system will prompt to enter a PIN code or confirm pairing
   

4. Connect/Disconnect Devices

   [bluetooth]# connect 00:11:22:AA:BB:CC  # Connect to a paired device
   [bluetooth]# disconnect 00:11:22:AA:BB:CC  # Disconnect
   

5. Trust Devices (Auto-connect)

   [bluetooth]# trust 00:11:22:AA:BB:CC  # Set as a trusted device
   [bluetooth]# untrust 00:11:22:AA:BB:CC  # Remove trust
   

4G

The RK3576 carrier board is equipped with an M.2 B KEY slot (on the back of the carrier board), which can connect to a 4G module for USB-based communication.

quectel-CM is pre-installed in /dfrobot-test. You can use the quectel-CM tool to establish a 4G dial-up connection.
The complete operation process is as follows:

1. Dial-Up Connection
   Use quectel-CM to establish a dial-up connection:

   # Navigate to the dfrobot-test directory
   # cd /dfrobot-test
   
   # Basic dial-up command
   # sudo ./quectel-CM -s [APN Name] &
   
   # China Telecom example
   # sudo ./quectel-CM -s ctnet &
   
   # China Mobile example
   # sudo ./quectel-CM -s cmnet &
   
   # China Unicom example
   # sudo ./quectel-CM -s 3gnet &
   

2. Connection Verification

# Check network interface status
# ip addr show wwan0

# Test network connectivity
# ping -I wwan0 8.8.8.8

External General Interfaces

USB

The RK3576 supports two USB 2.0 interfaces and two USB 3.2 Gen1x1 OTG interfaces (USB 3.2 Gen1x1 OTG1 shares pins with PCIE1 and SATA1).

The RK3576 carrier board provides:

• 1 Type‑C USB 3.1 Gen1 OTG interface
• 1 USB‑A USB 3.0 Gen1 Host interface
• 2 USB 2.0 interfaces (expanded via a hub chip)

Related Command-Line Instructions

# Switch to device mode
# sudo echo device > /sys/kernel/debug/usb/23000000.usb/mode

# Switch to USB host mode
# sudo echo host > /sys/kernel/debug/usb/23000000.usb/mode

# Mount the device
# sudo mount /dev/sda1 /mnt/

# Write test
# dd if=/dev/zero of=/mnt/test.txt bs=1M count=1024 oflag=direct status=progress

# Read test
# dd if=/mnt/test.txt of=/dev/null bs=1M count=1024 iflag=direct status=progress

# Delete the created test file
# sudo rm /mnt/test.txt

# Unmount the mount point
# sudo umount /mnt

After connecting the USB flash drive: Mount the storage device -> Test write performance -> Test read performance -> Clean up test files -> Unmount the device

Storage Interfaces

The RK3576 core board is equipped with on-board eMMC storage. The RK3576 carrier board features M.2 M KEY, TF card, and UFS storage interfaces (the UFS storage chip is not soldered on the carrier board).

eMMC

The RK3576 core board is equipped with on-board eMMC storage, compliant with the eMMC V5.1 specification and backward compatible with eMMC V4.51 and lower versions.

Related Command-Line Instructions

# Mount the device
# sudo mount /dev/sda1 /mnt/

# Write test
# dd if=/dev/zero of=/mnt/test.txt bs=1M count=1024 oflag=direct status=progress

# Read test
# dd if=/mnt/test.txt of=/dev/null bs=1M count=1024 iflag=direct status=progress

# Delete the created test file
# sudo rm /mnt/test.txt

# Unmount the mount point
# sudo umount /mnt

After connecting the USB flash drive: Mount the storage device -> Test write performance -> Test read performance -> Clean up test files -> Unmount the device

M.2 M Key

The RK3576 carrier board is equipped with an M.2 M Key slot, which supports a maximum power output of 29.5 W.
It can be connected to SSDs and computing cards to expand system storage capacity and computing power.

Related Command-Line Instructions

# Mount the device
# sudo mount /dev/sda1 /mnt/

# Write test
# dd if=/dev/zero of=/mnt/test.txt bs=1M count=1024 oflag=direct status=progress

# Read test
# dd if=/mnt/test.txt of=/dev/null bs=1M count=1024 iflag=direct status=progress

# Delete the created test file
# sudo rm /mnt/test.txt

# Unmount the mount point
# sudo umount /mnt

After connecting the SSD: Mount the storage device -> Test write performance -> Test read performance -> Clean up test files -> Unmount the device

MicroSD Card

The RK3576 development board is equipped with one TF Card interface for expandable system storage capacity.
It features a 4-bit data bus width and supports SD3.0 and MMC ver4.51.

Related Command-Line Instructions

# Mount the device
# sudo mount /dev/sda1 /mnt/

# Write test
# dd if=/dev/zero of=/mnt/test.txt bs=1M count=1024 oflag=direct status=progress

# Read test
# dd if=/mnt/test.txt of=/dev/null bs=1M count=1024 iflag=direct status=progress

# Delete the created test file
# sudo rm /mnt/test.txt

# Unmount the mount point
# sudo umount /mnt

After connecting the TF card: Mount the storage device -> Test write performance -> Test read performance -> Clean up test files -> Unmount the device

UFS

The RK3576 core board supports optional UFS storage.

Related Command-Line Instructions

# Mount the device
# sudo mount /dev/sda1 /mnt/

# Write test
# dd if=/dev/zero of=/mnt/test.txt bs=1M count=1024 oflag=direct status=progress

# Read test
# dd if=/mnt/test.txt of=/dev/null bs=1M count=1024 iflag=direct status=progress

# Delete the created test file
# sudo rm /mnt/test.txt

# Unmount the mount point
# sudo umount /mnt

Mount the storage device -> Test write performance -> Test read performance -> Clean up test files -> Unmount the device

CPU & NPU

CPU Benchmark

The RK3576 integrates a 4-core Cortex-A72 processor and a 4-core Cortex-A53 processor:

• Cortex-A72
  • Each core has a 45KB L1 instruction cache and a 32KB L1 data cache
  • 1MB unified L2 cache
• Cortex-A53
  • Each core has a 32KB L1 instruction cache and a 32KB L1 data cache
  • 512KB unified L2 cache

Test Script
The script is located at /rockchip-test/cpu/cpu_stress_test.sh.
Please execute this script with root privileges to perform a stress test on the CPU.

# . /rockchip-test/cpu/cpu_stress_test.sh

NPU Inference Test

The RK3576 features a built-in NPU that supports mixed operations of INT4/INT8/INT16/FP16/BF16/TF32.
In addition, with its strong compatibility, network models based on a series of frameworks such as TensorFlow/MXNet/PyTorch/Caffe can be easily converted.

• Supports sparse computing of 6TOPS@INT8
• Supports dual-core collaborative work or single-core independent work
• Supports mixed operations of INT4/INT8/INT16/FP16/BF16/TF32
• Supports 1MB internal SRAM
• Supports parallel operation of multiple scenarios and multiple tasks
• Supports deep learning frameworks: TensorFlow, Caffe, Tflite, Pytorch, Onnx NN, Android NN

Test Script
The script is located at /rockchip-test/npu2/npu_stress_test.sh.
Please execute this script with root privileges to view the NPU inference performance.

# . /rockchip-test/npu2/npu_stress_test.sh