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In this lecture, I will explain the structure of the HLS code for the Home Alarm System project 
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explained in the previous lecture.
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The design code should contain a top-function. The top-function should check all the sensors for any 
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security breach and send the proper information to the display panel.
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Two separate sub-functions help to send window or motion sensors information to the 7-segment displays.
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We also need a testbench to test the design behaviour.
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The test starts with the C/C++ main function.
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The function generates the input data and applies them to the design 
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and the golden software model and compares the results.
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The design top-function receives two groups of input signals and generates three groups of output signals.
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Here, two 16-bit and  5-bit arbitrary precision call-by-value arguments are used to read the slide 
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switches and push-buttons. Also, three 16-bit, 8-bit and 4-bit arbitrary precision 
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call-by-reference 
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arguments are defined to provide data for LEDs and seven-segments.
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We define an array to represent the seven-segment code in the design. Later we refer to this array to
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extract the desired code for 7-segments.
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The data format in the 16-bit slide_switches argument was presented in the previous lecture.
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In the first step, the top-function splits these data into different variables.
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Also, it saves the push_button states into a 5-bit variable with a more descriptive name.
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Then it directly connects all the slide-switches to LEDs. 
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The top-function should check the value of the code to see if the system is ON or OFF. According to 
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the project definition 
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in the previous lecture, the binary code of 1011 turns on the system.
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If the system is OFF, then all the 7-segments should display the letter O or the number 0.
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If the system is ON, then the output of the sensors should be checked. If there is any activation 
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in sensors, then the security_breach function is called for more inspection. 
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Otherwise, all the 7-segment displays should show the letter A.
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Now let’s have a look at the security_breach sub-function.
Firstly, it sends the letter E to all 
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7-segments. Then, it checks the pattern on the show_fault variable (which represents the push-buttons 
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sates).
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If any of the push_buttons is pressed, then the code checks whether it is related to the window sensors 
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or the motion sensors. And call the corresponding function for displaying the proper number on 
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seven segments.
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Let’s have a look at the display_window function. Before that, it is helpful to remember the data format 
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of the show_fault variable explained in the previous lecture.
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This function sends the letter E to all 7-segments again. 
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This process is done to make sure that the 7-segments receive data for all paths inside
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the function.
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Otherwise, as some paths may not generate data for the 7-segments than the HLS code saves 
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the previous values, 
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that means it should instantiate some flip-flips. 
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Consequently, the resulted circuit won’t be combinational. 
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Then the function modifies the 7-segment data according to the value of show_fault variable and 
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the sensor outputs.
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The display_motion function also has a similar structure and generates the corresponding 7-segment 
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data base on the value of show_fault variable and the motion sensors outputs.
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The test bench, firstly, define the status variables which keeps the status of the test. And report that 
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properly.
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Then it declares a couple of variables for design and software implementation inputs and outputs.
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Then using four nested for-loops, it generates all the possible inputs and prepares the design input 
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data.
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Then it calls the design and the software model and compares the results. 
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The next lecture puts all the codes in a Vivado-HLS project and generates the bitstream and examine 
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the system on the Basys-3 board.