I have written up/down counter and created code for settable starting point. So far so good but I can't think of how to add it to the counter. I have to highlight that I'm completely new to Verilog and similar languages.
//UTILS
reg [2:0] delay;
wire clock;
reg[3:0] tens;
reg[3:0] units;
wire[5:0] number;
reg[13:0] shift;
integer i;
//ASSIGNS
assign number[5:0] = SW[5:0];
assign up = SW[7];
assign start = SW[6];
//PRESCALER
always@ (posedge MCLK)
begin
delay <= delay + 1;
end
assign clock = &delay;
//MAIN COUNTER
always@ (posedge clock)
begin
if (start)
begin
if (up) //going up
begin
if (units == 4'd3 && tens == 4'd6)
begin //63 reached
units <= 0;
tens <=0;
end
if (units==4'd9)
begin //x9 reached
units <= 0;
tens <= tens + 1;
end
else
units <= units + 1; //typical case
end
else //goin down
begin
if (units == 4'd0)
if ( tens ==4'd0) //00 reached back to 63
begin
units <= 4'd3;
tens <= 4'd6;
end
else
begin //x0 reached
tens <= tens-1;
units <= 4'd9;
end
else
begin //typical case
units <= units -1;
end
end
end
end //MAIN COUNTER END
Here I don't know how to merge this two pieces, I would love to have it like this if start always@ posedge clock /counting/ else /* change number nearly functionally(immediately when change occurs)*/
Adding it into if(start) else seems to do the work but only on positive edge of quite low frequency clock. As far as I know i can't use one reg in two different ALWAYS@.
/* // Clear previous number and store new number in shift register
shift[13:6] = 0;
shift[5:0] = number;
//BINARY TO BCD
for (i=0; i<6; i=i+1)
begin
if (shift[9:6] >= 5)
shift[9:6] = shift[9:6] + 3;
if (shift[13:10] >= 5)
shift[13:10] = shift[13:10] + 3;
shift = shift << 1;
end
units <= shift[9:6];
tens <= shift[13:10];
*/
dek7seg Is 7-segment display which is 100% fine (professor's code).
dek7seg ss1(
.bits(units[3:0]),
.seg(DISP1[6:0])
);
dek7seg ss10(
.bits(tens[3:0]),
.seg(DISP2[6:0])
);
endmodule
You are using a derived clock to control your MAIN COUNTER. Instead use the main clock MCLK
and use the logic for delay
as a conditional statement.
Since you want store an new values on the change of number
, then you will need to store the the previous number
value and compare.
Based on your description, your code should look something like this:
//MAIN COUNTER
always@ (posedge MCLK)
begin
if (start && &delay)
begin
/* your up/down logic here */
end
else if (number != prev_number)
begin // Clear previous number and store new number
prev_number <= number;
units <= new_units;
tens <= new_tens;
end
end
// Calculate new units and tens from number
always @* begin
shift[13:6] = 0;
shift[5:0] = number;
//BINARY TO BCD
for (i=0; i<6; i=i+1) begin
if (shift[9:6] >= 5)
shift[9:6] = shift[9:6] + 3;
if (shift[13:10] >= 5)
shift[13:10] = shift[13:10] + 3;
shift = shift << 1;
end
new_units = shift[9:6];
new_tens = shift[13:10];
end