From the course: Learning FPGA Development

Demo system for the Xilinx platform - FPGA Tutorial

From the course: Learning FPGA Development

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Demo system for the Xilinx platform

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- [Instructor] Now for the Xilinx system, I need you to take a look at the basis three board reference manual. Here we have the schematic diagram of the basic input output on the board. At the center we have the Artix-7 FPGA and at the bottom we have the seven-segment display architecture. As you can see the bottom lines are the segment cathode activators and the top lines, the ones that are connected to those transistors are the anode activators. The way you use this display is by activating one anode that is you're activating one single digit and the number you are sending out in the cathode lines is the number that will be displayed at that particular digit. If you turn on all four anodes the same number will display in all four digits. This is not what we want, so this is implemented in this way to save the number of pins you are going to use in driving all of those digits and the way to use this display is to blink all of the digits one at a time showing the appropriate number that you want to show at each digit. This may not sound so good at first but this is taking advantage of a phenomenon called the persistence of vision that is when you are blinking something very, very fast, you can fool the human eye into seeing motion or seeing something that is not changing. That's how a TV screen used to work, so the algorithm turns on one digit then the next digit, then the next digit, then the next digit over and over again several times per second many times per second. In our example we will blink the whole display 60 times per second that is enough to fool your eyes. Well, as you can see this requires a sequential digital system.

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