Reference design puts low-cost remote image sensor signalling on programmable devices

April 16, 2013 // By Paul Buckley
Lattice Semiconductor's SensorExtender reference design remotely locates image sensors up to 8m away from the image signal processor (ISP) and transmits and receives video signals at resolutions that range up to 720p60 and 1080p30.

The reference design uses low-cost Cat5E cable to carry high-definition video and to send I 2C sensor control signals from the ISP during the vertical blanking period. Three twisted pairs carry the video and commands while a fourth pair provides power and ground to the remotely located sensors.

The solution serves applications that require image sensors to be separated from the image signal processor, which are often placed in tight spaces without room for adjacent ISPs to process the image. Typical applications include medical probes, large screen TVs with an integrated HD camera, surveillance domes, piping inspection ports, and point-of-sale scanners. The SensorExtender may link a single sensor to an ISP or connect a number of sensors to a central processor.

The reference design uses two Lattice MachXO2 low density FPGAs: one is placed next to the image sensor and the other is located just before the ISP.  A single twisted pair CAT5E/6 cable connects the two.

The SensorExtender solution offers a variety of interfaces (before serialisation) for CSI-2, HiSPi, parallel, or sub-LVDS image sensors along with support for extending two or more image sensors.  Additionally, the reference design allows parallel or serial ISP interfaces (after-deserialisation). Designers can configure parallel interfaces to handle 1.8 V, 2.5 V, or 3.3 V LVCMOS levels.

The reference design is tested with the Aptina MT MT9M024 and the Lattice HDR-60 camera development kit’s base board.  

Designers who already have Lattice’s HDR-60 Video Camera Development Kit can purchase the SensorExtender kit; part number LCMXO2-4000HE-SEC-EVN. The price is $295.00 and is available now.  The additional cost for the HDR-60 development kit is $425.00.  

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