Design Idea - HD Camera System Using USB 3.0 Interfacing

There are a growing number of applications outside the home entertainment sphere where better HD image quality could be of major benefit. Among these are security, medical imaging and factory line inspection. However in order to witness the improvements in resolution, contrast, colour depth and frame rates that adoption of HD technology offer, advanced semiconductor solutions with significantly higher data transfer capabilities will be required.

USB 3.0 is pushing up data rates and now presents a broad cross section of underserved industry sectors with the opportunity to implement higher performance video imaging systems that are still cost effective to deploy. Almost an order of magnitude faster than USB 2.0, it is fully backward compatible and still has the same plug-and-play convenience through which the standard originally gained universal appeal. USB 3.0 not only supports ultra-fast data transfer, it does so up to 10m, whereas alternative technologies struggle to cope with more than a few m of cabling. With this approach to video imaging, power delivery is covered - so there is just one cable feed between the camera and the data acquisition system, rather than separate ones for video data and power. This last point will prove advantageous in remote video applications, such as surveillance and industrial monitoring, where installing of multiple cables will be a drawback and ramp up deployment costs.

In the example shown here, a 2560x1440 pixel microscope camera is used for streaming imaging data to a HD monitor via USB 3.0. Data transfer takes place at 2.08Gbps, so that a high resolution frame rate of 38fps can be maintained without any lag or image distortion. As well as delivering dramatically higher data rates than one founded upon USB 2.0, this system can also benefit from the higher power levels that USB 3.0 (900mA while transferring data at full speed, as opposed to 480mA for USB 2.0). The USB 3.0 data transfer functionality is provided by FTDI Chip’s FT601 interface IC. The camera control and data capture functions of the system are both handled by the accompanying FPGA (in this particular case a Xilinx Spartan 6). The FPGA is responsible for the imaging system’s timing functions - setting the frame rate, etc. From there the acquired data is passed to the 32-bit parallel data bus incorporated into the FT601. The data is then transferred to the PC via USB 3.0 before being shown on the monitor.

 So that simplified implementation is assured, the various internal sub-units of the FT601 are controlled by its hardwired processor. This is based on the proprietary 32-bit core running at 100MHz. Through it engineers can configure the IC to fit with their exact application criteria.