SUB2r camera is built on a Cypress FX3 chipset that facilitates the Super-Speed USB 3.0+ communication between the device and a host system. Every component of the camera, be it an FPGA or an image sensor, receives user commands via that Cypress FX3.

On Windows the device is registered with a GUID {36FC9E60-C465-11CF-8056-444553540000} and if you are not planning on using the SUB2r-lib for your development - that would be the GUID to search for to properly connect to the command channel.

Here's a sample code that shows how to send commands to both the FX3 Host (defined on this page) and to access FPGA's mapped registers. The code lacks error checking (for clarity) and this should go without saying that if you copy-paste it into your code you must add error handling :)

// set a new auto-functions' update interval to 2x the default
// just issue the command directly to FX3's vendor request interface
void setAUInterval(){
    S2R::FX3 fx3;
    fx3.open(0);
    fx3.vrCmd(S2R::FX3::af_au_period, S2R::FX3::write, 6000, 0);
}
 
// run DPC calibration - also just a straight-up vendor request command to FX3
void runDPC(UCHAR _threshold = 240){
    S2R::FX3 fx3;
    fx3.open(0);
    fx3.vrCmd(S2R::FX3::calibrate_dpc, S2R::FX3::write, _threshold, 0);
}
 
// increase LED's green brightness by 25%
// utilize the FPGA's I²C bridge
void lightUpTheGreen(){
    using Cmd = S2R::FX3::Fx3Cmd;
    using OpType = S2R::FX3::VrCmdOpType;
 
    S2R::FX3 fx3;
    fx3.open(0);
    uint8_t        buf[1]{0};
    // LED green is mapped to register 0x0A ONLY for Gen3 and Gen4, won't work for Gen5
    const uint16_t clrChannel{0x0A};
    fx3.vrCmd(Cmd::i2c_bridge_fpga, OpType::read, 0, clrChannel, buf, 1);
    buf[0] += buf[0] / 4;  // yes, this can totally overflow
    fx3.vrCmd(Cmd::i2c_bridge_fpga, OpType::write, buf[0], clrChannel);
}

This applies to both FX3 and FPGA firmware version info data structures.

The bits are laid out in 4 sequential bytes as follows:

The FX3 version structure is as follows (little-endian memory layout):

firmware-version.h

struct FwVersion{
    unsigned vendorId    : 3;
    unsigned hwCfgId     : 5;
    unsigned productId   : 8;
    unsigned releaseType : 3;
    unsigned buildNo     : 13;
};
static_assert(sizeof(FwVersion) == 4);

The version id is also encoded into the firmware image file name as:

<VendorID>_<HardwareID>_<ProductID>_<ReleaseType>_<BuildNumber>

The version id is also encoded into the firmware image file name as:

<VendorID>_<HardwareID>_<ProductID>_<ReleaseType>_<BuildNumber>