Getting Started with GMSL2 Camera Splitter

Overview

The GMSL2 Camera Splitter, engineered by SZ SENSING TECH CO.,LTD., enables a single GMSL input to be distributed to two GMSL outputs while maintaining identical data streams. This device is compatible with SENSING GMSL camera models.

Key Features

• Lossless data transmission
• Full GMSL/GMSL2 compatibility
• Ultra-low latency (microsecond level)
• Minimal insertion loss

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Specifications

Parameter	Value
Transport Protocol	GMSL / GMSL2
Input Ports	1
Output Ports	2
Input Interface	1× GMSL2
Output Interface	2× GMSL2
Supported Data Rates	1.5Gbps, 3Gbps, 6Gbps
Maximum Resolution	Up to 3840×2160
Output Synchronization Accuracy	< 10μs
Power Supply	Yes
Connector	Fakra Z Type
Operating Temperature Range	-40°C to +85°C
Dimensions	87.5mm × 70.6mm × 20mm
Color	Black
Weight	< 150g

Dimensions

Hardware Overview

Block Diagram

I2C Address Information

	Device	I2C Address (8-bit)
1	Splitter: Logger	0x80
2	Splitter: ECU	0x80
3	Splitter: Camera	0x94
4	SENSING Camera	0x70

Connector Pin Definition

Connector Component	Part Number	Manufacturer/Note
Splitter Device Connector	50352-0400	Molex
Cable Harness Connector	50351-0400	Molex
Power Supply	Pin3, Pin4	9~12V DC
Ground	Pin1, Pin2	Common Ground

Cable Harness Definition

Product Models

Product Model	Input Channels	Output Channels	Resolution Support	Processor	Data Transfer Rate
SG2-BP0102-GMSL	1CH	2CH	Up to 1920×1080@30fps	MAX96705	1.5Gbps
SG8-BP0102-GMSL2	1CH	2CH	Up to 3840×2160@30fps	MAX9295A	6Gbps
SG8-BP0102-GMSL2F	1CH	2CH	Up to 1920×1080@30fps	MAX96717F	3Gbps

Getting Started

1. GMSL2 Camera Splitter Integration with Customer's Self-developed Platform

Using the Splitter when connecting to different domain controllers:

Splitter block diagram - Configuration for connecting to different domain controllers

Operating Procedure

1. Connect the system as shown in the diagram above.
2. Power up the Splitter first.
3. Initialize the Controller 1, which will power on and initialize the Splitter-ECU, followed by the Controller 2 power-on sequence and initialize the Splitter-Logger.
4. Execute normal operation commands from both Domain Controllers 1 and 2 to bring up the camera.

Operational Logic

1. Upon receiving power, the Splitter device automatically configures the connected camera.
2. Domain Controller 1 only needs to configure the Splitter as if it were a camera, then trigger it normally to activate the imaging pipeline.

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Refer to the software flow and example code below to develop your custom driver implementation.

2. Controller Software Development Example Code

1. Driver Development:

/* Example code for MAX9296 I2C initialization */
#define MAX9296_I2C_ADDR 0x90 // 8-bit address

int max9296_init() {
    // Initialize I2C bus
    i2c_init();
    
    // Disable MIPI output during configuration
    i2c_write(MAX9296_I2C_ADDR, 0x0313, 0x00);
    delay_ms(100);
    // Configure link settings for GMSL2 (6Gbps)
    i2c_write(MAX9296_I2C_ADDR, 0x0001, 0x02);

    // Configure linkA and linkB settings for GMSL2 selection (default value)
    i2c_write(MAX9296_I2C_ADDR, 0x0006, 0xC0);
    
    // Configure MIPI rate to 1200Mbps
    i2c_write(MAX9296_I2C_ADDR, 0x0320, 0x2C); 
    
    // Enable MIPI output
    i2c_write(MAX9296_I2C_ADDR, 0x0313, 0x02);
    
    return 0;
}

2. Splitter Configuration:

/* Example code for Splitter initialization */

#define MAX9295A_I2C_ADDR 0x80 // 8-bit address

int Splitter_init() {
    // Initialize deserializer first
    max9296_init();
    
    // Reset ISP 
    i2c_write(MAX9295A_I2C_ADDR, 0x02BE, 0x10); // MFP0 high
    
    // Configure essential registers
    i2c_write(MAX9295A_I2C_ADDR, 0x0057, 0x12); 
    i2c_write(MAX9295A_I2C_ADDR, 0x005B, 0x11); 
    
    // Configure datatype to YUV422 8bit
    i2c_write(MAX9295A_I2C_ADDR, 0x0318, 0x5E); 

    // Camera trigger sequence: MFP7 low to high
    i2c_write(MAX9295A_I2C_ADDR, 0x02D3, 0x00); // MFP7 low
    delay_ms(300);
    i2c_write(MAX9295A_I2C_ADDR, 0x02D3, 0x10); // MFP7 high

    // Initialize sensor,if without ISP, skip this step
    sensor_init();

    return 0;
}

int sensor_init() { 
    // Initialize sensor
    i2c_write(sensor_I2C_ADDR, 0x0102, 0x0001);
    // Additional sensor initialization parameters
    // (Refer to Camera Information documentation for the complete sensor register configuration)
}

Integration Steps

1. BSP Integration:

   • Modify the device tree to include the GMSL2 interface configuration
   • Add the camera driver to kernel build configuration
   • Configure the media controller pipeline for the camera

2. Application Development:

/* Example code for capturing camera frames */
#include "camera_api.h"

int main() {
    // Open camera device
    int fd = open("/dev/video0", O_RDWR);
    if (fd < 0) {
        perror("Failed to open camera device");
        return -1;
    }
    
    // Configure video capture format
    struct v4l2_format fmt = {0};
    fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    fmt.fmt.pix.width = 1920;
    fmt.fmt.pix.height = 1536;
    fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
    
    if (ioctl(fd, VIDIOC_S_FMT, &fmt) < 0) {
        perror("Failed to set format");
        close(fd);
        return -1;
    }
    
    // Request and map buffers
    // ... (buffer setup code) ...
    
    // Start streaming
    // ... (streaming code) ...
    
    // Capture and process frames
    // ... (frame processing code) ...
    
    // Cleanup
    close(fd);
    return 0;
}

Step 2: Data Processing

After receiving the module data through the GMSL2 interface:

• Data Reception
  • GMSL2 protocol implementation
  • Data rate configuration
• Image Processing Pipeline
  • YUV422 8bit data parsing
  • Image format conversion

Technical Support

• Documentation

  • Comprehensive register descriptions
  • Integration guides

• Engineering Support

  • Technical consultation
  • Debugging assistance
  • Performance optimization

tip

SENSING Technology provides expert technical support for integration with most platforms. For detailed documentation, sample code, and technical assistance, please contact our support team.