I have a DE-10 lite FPGA with the Digilent PMOD Keypad and I'm trying to increment a counter every time a button on the keypad is pressed. I'm trying to increase a counter so that I may know how many buttons have been pressed while in the current state. I followed the example code from Digilent and am trying to detect keypresses through a polling technique shown below:
module keypad(input clk, input [3:0] row, output reg [3:0] column, output reg [3:0] decode);
reg [19:0] clock_count;
always @ (posedge clk)
begin
////////////////////////
if (clock_count == 20'd50000) // column 0 check
begin
column <= 4'b0111;
clock_count <= clock_count + 1'b1;
end
else if(clock_count == 20'd50008) // column 0 rows check after column activated
begin
if (row == 4'b0111) decode <= 4'b0001; // row 0 -> key '1'
else if(row == 4'b1011) decode <= 4'b0100; // row 1 -> key '4'
else if(row == 4'b1101) decode <= 4'b0111; // row 2 -> key '7'
else if(row == 4'b1110) decode <= 4'b0000; // row 3 -> key '0'
clock_count <= clock_count + 1'b1;
end
////////////////////////
else if (clock_count == 20'd100000) // column 1 check
begin
column <= 4'b1011;
clock_count <= clock_count + 1'b1;
end
else if(clock_count == 20'd100008) // column 1 rows check after column activated
begin
if (row == 4'b0111) decode <= 4'b0010; // row 0 -> key '2'
else if(row == 4'b1011) decode <= 4'b0101; // row 1 -> key '5'
else if(row == 4'b1101) decode <= 4'b1000; // row 2 -> key '8'
else if(row == 4'b1110) decode <= 4'b1111; // row 3 -> key 'F'
clock_count <= clock_count + 1'b1;
end
////////////////////////
else if(clock_count == 20'd150000) // column 2 check
begin
column <= 4'b1101;
clock_count <= clock_count + 1'b1;
end
else if(clock_count == 20'd150008) // column 2 rows check after column activated
begin
if(row == 4'b0111) decode <= 4'b0011; // row 0 -> key '3'
else if(row == 4'b1011) decode <= 4'b0110; // row 1 -> key '6'
else if(row == 4'b1101) decode <= 4'b1001; // row 2 -> key '9'
else if(row == 4'b1110) decode <= 4'b1110; // row 3 -> key 'E'
clock_count <= clock_count + 1'b1;
end
////////////////////////
else if(clock_count == 20'd200000) // column 3 check
begin
column <= 4'b1110;
clock_count <= clock_count + 1'b1;
end
else if(clock_count == 20'd200008) // column 3 rows check after column activated
begin
if(row == 4'b0111) decode <= 4'b1010; // row 0 -> key 'A'
else if(row == 4'b1011) decode <= 4'b1011; // row 1 -> key 'B'
else if(row == 4'b1101) decode <= 4'b1100; // row 2 -> key 'C'
else if(row == 4'b1110) decode <= 4'b1101; // row 3 -> key 'D'
clock_count <= 20'd0; // restart clock counting
end
else begin
clock_count <= clock_count + 1'b1;
end
end
endmodule
My wrapping program is displayed below, and the biggest issue I am having is that I can't get input_counter in state0 to increase every time a button is pressed:
module calc_top(input fifty_MHz, input [3:0] row, output [3:0] column, input bttn1, output [47:0] hex, output [9:0] leds);
wire twentyfive_mhz;
twentyfive_mhz c0 (.clk(fifty_MHz), .twentyfive_mhz(twentyfive_mhz));
wire [3:0] keypad;
wire [3:0] keypad_decode;
reg [3:0] state_place = 4'd0;
wire [3:0] next_state;
reg [47:0] hex_disp;
reg reset = 1'b1;
always@(posedge twentyfive_mhz or negedge reset)
begin
if(~reset) state_place = 4'd0;
else state_place = next_state;
end
keypad k0 (.clk(twentyfive_mhz), .row(row), .column(column), .decode(keypad));
state0 a0 (.clk(clk), .state_place(state_place), .keypad_decode(keypad), .leds(leds));
endmodule
module state0(input clk, input [3:0] state_place, input [3:0] keypad_decode, output reg [9:0] leds, output reg [3:0] next_state);
reg [3:0] input_counter = 4'd0;
always@(keypad_decode)
begin
if(state_place == 4'd0)
begin
input_counter = input_counter + 4'd1;
case (keypad_decode)
4'h0 : begin
//hex_disp <= (hex_disp << (4*input_counter)) + 4'd0; // 0
leds <= 10'b0000000000;
next_state = 4'd0;
end
4'h1 : begin
//hex_disp <= (hex_disp << (4*input_counter)) + 4'd1; // 1
leds <= 10'b0000000001;
next_state = 4'd0;
end
4'h2 : begin
//hex_disp <= (hex_disp << (4*input_counter)) + 4'd2; // 2
leds <= 10'b0000000010;
next_state = 4'd0;
end
4'h3 : begin
//hex_disp <= (hex_disp << (4*input_counter)) + 4'd3; // 3
leds <= 10'b0000000011;
next_state = 4'd0;
end
4'h4 : begin
//hex_disp <= (hex_disp << (4*input_counter)) + 4'd4; // 4
leds <= 10'b0000000100;
next_state = 4'd0;
end
4'h5 : begin
//hex_disp <= (hex_disp << (4*input_counter)) + 4'd5; // 5
leds <= 10'b0000000101;
next_state = 4'd0;
end
4'h6 : begin
//hex_disp <= (hex_disp << (4*input_counter)) + 4'd6; // 6
leds <= 10'b0000000110;
next_state = 4'd0;
end
4'h7 : begin
//hex_disp <= (hex_disp << (4*input_counter)) + 4'd7; // 7
leds <= 10'b0000000111;
next_state = 4'd0;
end
4'h8 : begin
//hex_disp <= (hex_disp << (4*input_counter)) + 4'd8; // 8
leds <= 10'b0000001000;
next_state = 4'd0;
end
4'h9 : begin
//hex_disp <= (hex_disp << (4*input_counter)) + 4'd9; // 9
leds <= 10'b0000001001;
next_state = 4'd0;
end
4'hF : begin
leds <= 10'b0000001111;
next_state <= 4'd1;
end
default : begin
leds <= 10'b0000000000;
end
endcase
end
end
endmodule
I think I know what's happening... I think I'm required to have debouncing in order for this to work but I couldn't get the debouncing to work correctly with the current implementation.
Please help if you can! Thank you.
EDIT////////// I just got my debouncing circuit to work but the counter value still wont update.
