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Using the BCD and the 7-segment codes, here I am going to design a combinational circuit to show a 
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2-digit BCD number on the Basys3 7-segments. 
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Our goal is to convert a binary number into a two-digit BCD code and then show that on two 7-segments 
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available on the Baysis3 board. 
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Eight slide switches are used to enter a binary number less than 100 that has at most 
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two decimal digits. 
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The FPGA design reads this number, converts that to the corresponding BCD code and then sends that to 
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7-segments. 
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Up to now, we learned how to turn on only one 7-segment at a time. 
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So we use the push-buttons on the Basys3 board to choose between the two active 7-segments.
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We use eight right-hand switches for entering the binary number.  Two right-hand side 7segments 
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show the corresponding BCD number.
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We activate a 7segment at a time. The push-button switch at the top activates the second 
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7-segment, and the one at the left activates the first seven-segment.
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The HLS code that drives 7segments to show a number has five steps: 1- Defining input and 
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output mechanisms via top-function arguments.
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2- Encoding the input binary to BCD. 3- Checking the push-button states. 4-Encoding 
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the BCD to the 7-segment code. 5- Sending the code to 7-segments. Before starting to implement 
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these five steps, 
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let’s define a few data types for the HLS code. 
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We use arbitrary precision unsigned integer data types for this purpose. In the code, we need 16-bit, 
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8-bit, 4-bit and 2-bit data types. 
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Now, let’s write the HLS top-function.  Firstly, the code should define a few arguments for inputs and 
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outputs.
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The in_binary and push_button variables are defined for receiving the input binary number and the
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push-buttons’ states. 
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The outputs are the signals for driving the 7-segments that are control and data signals. 
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So the two-pointer arguments code and anodes carry data and control signals, respectively.
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Then the input binary should be converted to the equivalent BCD. This conversion can be done by calling 
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the function that we wrote in the previous lecture.
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Then we check the push buttons to know which 7segment should be activated.
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Then, we convert the BCD into 7-segment code using the algorithm explained in the 
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7Segment-OneDigit lecture.
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Finally, we send the results out. But, before that, we need to define the ports interfaces.
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Synthesising the code using the Xilinx Vivado-HLS and Vivado tools and generating the FPGA bitstream 
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are our tasks for the next lecture. 
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Also, we program the board to check the design. 
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This is the takeaway message. Push-button switches can be used to get temporary inputs
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Now the quiz. Write an HLS description to show a 4-digit number on 7-segments. Use
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4-push-buttons, as shown in the picture to activate each 7-segment.