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A Very Short Conversation with Ximea about Subminiature Video Cameras and Very Small FPGAs

by Xilinx Employee ‎02-02-2017 01:00 PM - edited ‎02-02-2017 09:54 PM (15,203 Views)


Yesterday at Photonics West, my colleague Aaron Behman and I stopped by the Ximea booth and had a very brief conversation with Max Larin, Ximea’s CEO. Ximea makes a very broad line of industrial and scientific cameras and a lot of them are based on several generations of Xilinx FPGAs. During our conversation, Max removed a small pcb from a plastic bag and showed it to us. “This is the world’s smallest industrial camera,” he said while palming a 13x13mm board. It was one of Ximea’s MU9 subminiature USB cameras based on a 5Mpixel ON Semiconductor (formerly Aptina) MT9P031 image sensor. Ximea’s MU9 subminiature camera is available as a color or monochrome device.


Here’s are front and back photos of the camera pcb:



Ximea MU9 Subminiature Camera.jpg


Ximea 5Mpixel MU9 subminiature USB camera



As you can see, the size of the board is fairly well determined by the 10x10mm image sensor, its bypass capacitors, and a few other electronic components mounted on the front of the board. Nearly all of the active electronics and the camera’s I/O connector are mounted on the rear. A Cypress CY7C68013 EZ-USB Microcontroller operates the camera’s USB interface and the device controlling the sensor is a Xilinx Spartan-3 XC3S50 FPGA in an 8x8mm package. FPGAs with their logic and I/O programmability are great for interfacing to image sensors and for processing the video images generated by these sensors.


Our conversation with Max Larin at Photonics West got me to thinking. I wondered, “What would I use to design this board today?” My first thought was to replace both the Spartan-3 FPGA and the USB microcontroller with a single- or dual-core Xilinx Zynq SoC, which can easily handle all of the camera’s functions including the USB interface, reducing the parts count by one “big” chip. But the Zynq SoC family’s smallest package size is 13x13mm—the same size as the camera pcb—and that’s physically just a bit too large.


The XC3S50 FPGA used in this Ximea subminiature camera is the smallest device in the Spartan-3 family. It has 1728 logic cells and 72Kbits of BRAM. That’s a lot of programmable capability in an 8x8mm package even though the Spartan-3 FPGA family first appeared way back in 2003. (See “New Spartan-3 FPGAs Are Cost-Optimized for Design and Production.”)


There are two newer Spartan FPGA families to consider when creating a design today, Spartan-6 and Spartan-7, and both device families include multiple devices in 8x8mm packages. So I decided see how much I might pack into a more modern FPGA with the same pcb real-estate footprint.


The simple numbers from the data sheets tell part of the story. A Spartan-3 XC3S50 provides you with 1728 logic cells, 72Kbits of BRAM, and 89 I/O pins. The Spartan-6 XCSLX4, XC6SLX9, and XCSLX16 provide you with 3840 to 14,579 logic cells, 216 to 576Kbits of BRAM, and 106 I/O pins. The Spartan-7 XC7S6 and XC7S15 provide 6000 to 12,800 logic cells, 180 to 360Kbits of BRAM, and 100 I/O pins. So both the Spartan-6 and Spartan-7 FPGA families provide nice upward-migration paths for new designs.


However, the simple data-sheet numbers don’t tell the whole story. For that, I needed to talk to Jayson Bethurem, the Xilinx Cost Optimized Portfolio Product Line Manager, and get more of the story. Jayson pointed out a few more things.


First and foremost, the Spartan-7 FPGA family offers a 2.5x performance/watt improvement over the Spartan-6 family. That’s a significant advantage right there. The Spartan-7 FPGAs are significantly faster than the Spartan-6 FPGAs as well. Spartan-6 devices in the -1L speed grade have a 250MHz Fmax versus 464MHz for Spartan-7 -1 or -1L parts. The fastest Spartan-6 devices in the -3 speed grade have an Fmax of 400MHz (still not as fast as the slowest Spartan-7 speed grade) and the fastest Spartan-7 FPGAs, the -2 parts, have an Fmax of 628MHz. So if you feel the need for speed, the Spartan-7 FPGAs are the way to go.


I’d be remiss not to mention tools. As Jayson reminded me, the Spartan-7 family gives you entrée into the world of Vivado Design Suite tools. That means you get access to the Vivado IP catalog and Vivado’s IP Integrator (IPI) with its automated integration features. These are two major benefits.


Finally, some rather sophisticated improvements to the Spartan-7 FPGA family’s internal routing architecture means that the improved placement and routing tools in the Vivado Design Suite can pack more of your logic into Spartan-7 devices and get more performance from that logic due to reduced routing congestion. So directly comparing logic cell numbers between the Spartan-6 and Spartan-7 FPGA families from the data sheets is not as exact a science as you might assume.


The nice thing is: you have plenty of options.



For previous Xcell Daily blog posts about Ximea industrial and scientific cameras, see:





About the Author
  • Be sure to join the Xilinx LinkedIn group to get an update for every new Xcell Daily post! ******************** Steve Leibson is the Director of Strategic Marketing and Business Planning at Xilinx. He started as a system design engineer at HP in the early days of desktop computing, then switched to EDA at Cadnetix, and subsequently became a technical editor for EDN Magazine. He's served as Editor in Chief of EDN Magazine, Embedded Developers Journal, and Microprocessor Report. He has extensive experience in computing, microprocessors, microcontrollers, embedded systems design, design IP, EDA, and programmable logic.