whitexlion
Newbie level 1
Hey guys, I was wondering if I could get some help on something I'm working on. I'm very new to Verilog, so I'm not really the best / most efficient at it. I'm trying to get a counter to start counting down when a push button is pressed. I currently have it so that when I press and hold the button, it counts, but when I release it, the counter the stops counting down. Here's the code that I have so far. (I'm using a Nexys2 Spartan3E board)
I was thinking of possibly making a different module for the counting, and just activate that when the button is pressed once.
When I do get the program counting down on button press, I also will have a statement to set a variable to 1 when a certain input is entered on the switches, so I was wondering if I can lock out the switch inputs while the counter is not counting down.
Thanks in advance.
Code:
`timescale 1ns / 1ps
module countonpb(
input clock, pb,
output reg [3:0] msbs,
output reg [3:0] lsbs,
output reg [6:0] sevseg,
output reg [3:0] an,
output reg [1:0] clk
);
reg [3:0] i;
reg [3:0] j;
integer count_a = 0;
integer count_50M = 0;
reg pb_press;
initial begin
an[0] <= 0;
an[1] <= 1;
an[2] <= 1;
an[3] <= 1;
i <= 9;
j <= 9;
end
always @ (posedge clk[0])
begin
an[0] <= ~an[0];
an[1] <= ~an[1];
an[2] <= 1;
an[3] <= 1;
msbs <= i;
lsbs <= j;
end
always @ (posedge clk[1])
begin
pb_press <= pb;
if (pb_press == 1)
begin
if (i == 0)
begin
i = 0;
j = j - 1;
end
else
begin
if (j == 0)
begin
i = i - 1;
j = 9;
end
else
j = j - 1;
end
end
end
always @ (posedge clk[0])
begin
if (an[1])
begin
case(msbs)
0: sevseg = 7'b0000001;
1: sevseg = 7'b1001111;
2: sevseg = 7'b0010010;
3: sevseg = 7'b0000110;
4: sevseg = 7'b1001100;
5: sevseg = 7'b0100100;
6: sevseg = 7'b0100000;
7: sevseg = 7'b0001101;
8: sevseg = 7'b0000000;
9: sevseg = 7'b0000100;
default: sevseg = 7'b0000001;
endcase
end
if (an[0])
begin
case(lsbs)
0: sevseg = 7'b0000001;
1: sevseg = 7'b1001111;
2: sevseg = 7'b0010010;
3: sevseg = 7'b0000110;
4: sevseg = 7'b1001100;
5: sevseg = 7'b0100100;
6: sevseg = 7'b0100000;
7: sevseg = 7'b0001101;
8: sevseg = 7'b0000000;
9: sevseg = 7'b0000100;
default: sevseg = 7'b0000001;
endcase
end
end
always @ (posedge clock) //slower clock
if (count_50M < 25000000) count_50M = count_50M + 1;
else
begin
clk[1] = ~clk[1];
count_50M = 0;
end
always @ (posedge clock) //slow clock
if (count_a < 25000) count_a = count_a + 1;
else
begin
clk[0] = ~clk[0];
count_a = 0;
end
endmoduleI was thinking of possibly making a different module for the counting, and just activate that when the button is pressed once.
When I do get the program counting down on button press, I also will have a statement to set a variable to 1 when a certain input is entered on the switches, so I was wondering if I can lock out the switch inputs while the counter is not counting down.
Thanks in advance.