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// This file is part of the Universal Laboratory (uLab)
//
// © 2007 - 2019 Raptor Engineering, LLC
// All Rights Reserved
//
// Licensed under the terms of the AGPL v3
module guest_fpga_top(clk, reset, four_bit_input, four_bit_output, eight_bit_input, eight_bit_output, sixteen_bit_input, sixteen_bit_output, lcd_data_in_address, lcd_data_in_data, lcd_data_in_enable, led_segment_bus, led_digit_select);
input clk;
input reset;
input [3:0] four_bit_input;
output reg [3:0] four_bit_output;
input [7:0] eight_bit_input;
output reg [7:0] eight_bit_output;
input [15:0] sixteen_bit_input;
output reg [15:0] sixteen_bit_output;
output reg [5:0] lcd_data_in_address;
output reg [7:0] lcd_data_in_data;
output reg lcd_data_in_enable;
output reg [7:0] led_segment_bus;
output reg [3:0] led_digit_select;
reg [7:0] lcd_sample_counter = 48; // Create a sample LCD display counter register
reg [31:0] lcd_character_change_timer = 0; // Wait a certain number of cycles before loading a new character
reg [5:0] lcd_current_character = 0; // The current character's address
always @(posedge clk) begin
four_bit_output = four_bit_input; // Loopback
eight_bit_output = eight_bit_input[3:0] + eight_bit_input[7:4]; // Sample adder
sixteen_bit_output = sixteen_bit_input[15:8] * sixteen_bit_input[7:0]; // Sample multiplier
// Sample LCD display routine
lcd_data_in_address = lcd_current_character; // Character location on the LCD display
lcd_data_in_data = lcd_sample_counter; // Character code to display
lcd_data_in_enable = 1; // Enable data transmission
// Cycle through all character positions
lcd_current_character = lcd_current_character + 1;
if (lcd_current_character > 31) begin
lcd_current_character = 16;
end
// Cycle through the numbers 0 to 9 at one second intervals
lcd_character_change_timer = lcd_character_change_timer + 1;
if (lcd_character_change_timer > 6000000) begin // Wait one second in between character changes
lcd_character_change_timer = 0;
lcd_sample_counter = lcd_sample_counter + 1;
if (lcd_sample_counter > 57) begin // Character code for the digit 9
lcd_sample_counter = 48; // Character code for the digit 0
end
end
end
// 7-segment LED display driver clock generator
reg sseg_clock;
reg [4:0] sseg_clock_counter;
always @(posedge clk) begin
sseg_clock_counter = sseg_clock_counter + 1;
if (sseg_clock_counter > 16) begin
sseg_clock_counter = 0;
sseg_clock = ~sseg_clock;
end
end
// 7-segment LED display driver
// led_segment_bus and led_digit_select are active low
// The bit sequence, MSB to LSB, is dp a b c d e f g
// Segment letters are taken from ug130.pdf page 15
// 0: 8'b10000001
// 1: 8'b11001111
// 2: 8'b10010010
// 3: 8'b10000110
reg [2:0] current_anode;
always @(posedge sseg_clock) begin
current_anode = current_anode + 1;
if (current_anode > 3) begin
current_anode = 0;
end
case (current_anode)
0: begin
led_digit_select = 4'b1110;
led_segment_bus = 8'b10000001;
end
1: begin
led_digit_select = 4'b1101;
led_segment_bus = 8'b11001111;
end
2: begin
led_digit_select = 4'b1011;
led_segment_bus = 8'b10010010;
end
3: begin
led_digit_select = 4'b0111;
led_segment_bus = 8'b10000110;
end
endcase
end
endmodule
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