Project

Project:

Interface a mouse with FPGA (From https://www.fpga4student.com/) (Finalized Project Topic)

Interface a mouse with FPGA:

Theoretical Workflow:
The primary objective of the project is to emulate a mouse with FPGA board.
The first digit indicates the status of the mouse idle/active
- 1|0|0|0|0|0|0|0|0|0|0
The left and right click of the mouse will be indicated by the next two bits of an 11 bit number like the following:
- 1|L|R|0|0|0|0|0|0|0|0
The coordinates of the mouse will be tracked by the middle four digits: Poisitive/Negative | X direction |Positive/Negative |Y direction
- 1|L|R|+-|X|+-|Y|0|0|0|0
- X indicates Left and Right
- Y indicates Up and Down
The last four digits indicates the speed of the mouse
- 0|L|R|+-|X|+-|Y|0|0|1|1
The precise location of the mouse are indicated by the value of X and Y coordinates with two 10 bits number.
- |X1|X2|X3|X4|X5|X6|X7|X8|X9|X10|
- |Y1|Y2|Y3|Y4|Y5|Y6|Y7|Y8|Y9|Y10|
- If modeled on an computer, the two 10 bit numbers will be the length and width of the computer screen
So when the mouse is activated when being right clicked or left clicked, it will send a 31 bit signal to the FPGA board. The FPGA board will in turn display a number that's increasing or decreasing depends on which button: left and right/ is clicked.
The number of bits will be monitored by a 6 bit signal mouse_bits (5 downto 0).
The displayed number counter will be represented by a 16 bit signal displayed_number(15 downto 0).
It will be converted to decimal numbers that will be displayed on the 4 digit 7 segment display.
The basic concept will be demonstrated by this video from fpga4students.com:

Design Obstacles and Reservations:

Without a fpga board, there is no concrete evidence that the theoretical code work as intended.
The online tutorial is written in terms of Basy 3 FPGA board not the Nexy 4 DDR board that the team is primarily working with in CPE-487.
Unfamiliarity with the VHDL syntax and the the language's nature of parallel execution instead of sequential can proved to be a huge hinderance to a smooth design flow.

VHDL Code:

library IEEE;

use IEEE.std_logic_1164.all;

entity mouse is

  port (mouse_clk     :  in std_logic_vector;

      reset           :  in std_logic_vector;      --reset all to zero;

      status          :  in std_logic_vector;      --status active/idle

      mouse_data      :  in std_logic_vector (1 downto 0);--left or right is clicked

      speed           :  in std_logic_vector (3 downto 0);

      displayed_number:  out std_logic_vector(6 downto 0);--7 segments

      anode           :  out std_logic_vector (3 downto 0);)--4 digits

end mouse;

architecture mouse_arc of mouse is

  dig                    : std_logic_vector (1 downto 0);--led activation

  mouse_bits             : std_logic_vector (5 downto 0);--number of bits received

  signal displayed_number: std_logic_vector(15 downto 0);

  signal led_bcd         : std_logic_vector(4 downto 0);

 //32 bit signal received from the mouse

   if(rising_edge(mouse_clk)||rising_edge(reset)) then

     if(reset==1) // resetting the mouse bits and displayed number

      mouse_bits <= 0;

     else if(mouse_bits<=31) //if the bits received from mouse is smaller than 31 bit

      mouse_bits <= mouse_bits+1;

     else

      mouse_bits <= 0;

end

//Displayed number increment/decrement when the right or left button of the mouse is clicked

  if(falling_edge(mouse_clk)||rising_edge(reset)) then

    if(reset==1)

      displayed_number <=0;

    else begin

      if(status ==1) then//mouse is active

        if(mouse_data == "01") then//right button is pressed

          displayed_number <= displayed_number + 1;

end

        else if(mouse_data == "10"&&displayed_number>0) then//left button is pressed

          displayed_number <= displayed_number -1;

end

        else if(mouse_data =="11" || mouse_data =="00") then//inactive or both buttons

          displayed_number <= displayed_number;

end

end

end

//converting the displayed_number to numeric number to be displayed on the 4-digit displayer

  begin

    case(dig)

    2'b00: begin

      anode = 4'b0111;

      led_bcd = displayed_number/1000;

end

    2'b01: begin

      anode = 4'b1011

      led_bcd = displayed_number%1000/100;

end

    2'b10:

      begin

      anode = 4'b1101

      led_bcd = displayed_number%1000%100/10;

end

    2'b11: begin

      anode = 4'b1110

      led_bcd = displayed_number%1000%100%10;

end

    endcase

end

  begin

    case(led_bcd)

    4'b0000: displayed_number = 7'b0000001; --"0"

    4'b0001: displayed_number = 7'b1001111; --"1"

    4'b0010: displayed_number = 7'b0010010; --"2"

    4'b0011: displayed_number = 7'b0000110; --"3"

    4'b0100: displayed_number = 7'b1001100; --"4"

    4'b0101: displayed_number = 7'b0100100; --"5"

    4'b0110: displayed_number = 7'b0100000; --"6"

    4'b0111: displayed_number = 7'b0001111; --"7"

    4'b1000: displayed_number = 7'b0000000; --"8"

    4'b1001: displayed_number = 7'b0001000; --"9"

    default: displayed_number = 7'b1111111;

    endcase

end

end

Pin Constraint File:

For the pin constraint file, I have to understand it fullly from scratch, becaue of my lack of understanding in its pivotal role to make a Xilinix Project Work.
So I went on this website https://reference.digilentinc.com/learn/software/tutorials/vivado-xdc-file to catch up and this website offers a great explaination on what a XDC file does.

##Switches

set_property -dict { PACKAGE_PIN J15   IOSTANDARD LVCMOS33 } [get_ports { mouse_clk }];

IO_L24N_T3_RS0_15 Sch=mouse_clk

set_property -dict { PACKAGE_PIN L16   IOSTANDARD LVCMOS33 } [get_ports { mouse_data }];

IO_L3N_T0_DQS_EMCCLK_14 Sch=mouse_data

set_property -dict { PACKAGE_PIN M13   IOSTANDARD LVCMOS33 } [get_ports { reset }]; IO_L6N_T0_D08_VREF_14 Sch=reset

set_property -dict { PACKAGE_PIN R15   IOSTANDARD LVCMOS33 } [get_ports { status }];

IO_L13N_T2_MRCC_14 Sch=status

## LEDs

set_property -dict { PACKAGE_PIN H17   IOSTANDARD LVCMOS33 } [get_ports { LED[0] }]; IO_L18P_T2_A24_15 Sch=led[0]

set_property -dict { PACKAGE_PIN K15   IOSTANDARD LVCMOS33 } [get_ports { LED[1] }]; IO_L24P_T3_RS1_15 Sch=led[1]

set_property -dict { PACKAGE_PIN J13   IOSTANDARD LVCMOS33 } [get_ports { LED[2] }]; IO_L17N_T2_A25_15 Sch=led[2]

set_property -dict { PACKAGE_PIN N14   IOSTANDARD LVCMOS33 } [get_ports { LED[3] }]; IO_L8P_T1_D11_14 Sch=led[3]

set_property -dict { PACKAGE_PIN R18   IOSTANDARD LVCMOS33 } [get_ports { LED[4] }]; IO_L7P_T1_D09_14 Sch=led[4]

set_property -dict { PACKAGE_PIN V17   IOSTANDARD LVCMOS33 } [get_ports { LED[5] }]; IO_L18N_T2_A11_D27_14 Sch=led[5]

set_property -dict { PACKAGE_PIN U17   IOSTANDARD LVCMOS33 } [get_ports { LED[6] }]; IO_L17P_T2_A14_D30_14 Sch=led[6]

set_property -dict { PACKAGE_PIN H15   IOSTANDARD LVCMOS33 } [get_ports { DP }]; #IO_L19N_T3_A21_VREF_15 Sch=dp

#set_property -dict { PACKAGE_PIN J17   IOSTANDARD LVCMOS33 } [get_ports { anode[0] }]; #IO_L23P_T3_FOE_B_15 Sch=anode[0]

#set_property -dict { PACKAGE_PIN J18   IOSTANDARD LVCMOS33 } [get_ports { anode[1] }]; #IO_L23N_T3_FWE_B_15 Sch=an[1]

#set_property -dict { PACKAGE_PIN T9    IOSTANDARD LVCMOS33 } [get_ports { anode[2] }]; #IO_L24P_T3_A01_D17_14 Sch=an[2]

#set_property -dict { PACKAGE_PIN J14   IOSTANDARD LVCMOS33 } [get_ports { anode[3] }];

Conclusion:

Interfacing a mouse would be extremely hard without an actual Nexy4 DDS board since trial and error are out of the equation.
However, with the concise and simple demonstration offered by fpga4students.com, it is easy to conjecture what needs to be done for the VHDL and XDC file that ensues.
There were a lot of syntactical errors that need to be corrected before importing the files into Vivado and start running synthesis and opening implemenation design.
The synthesis failed before the syntactical error correction
After the correction, the Screenshots below shows the file in Vivado Design Suite and the bitstream is generated successfully.
It is needed that I save the VHDL code and XDC files so that when the global pandemic abates and school is reopened, I can go back to test out and verify the results of the interfacing a mouse project.

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