aboutsummaryrefslogtreecommitdiffstats
path: root/tests/ice40/adffs.v
blob: 93c8bf52c75c87ba9282d58eb785ef20458ad58e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
module adff
    ( input d, clk, clr, output reg q );
    initial begin
      q = 0;
    end
	always @( posedge clk, posedge clr )
		if ( clr )
			q <= 1'b0;
		else
            q <= d;
endmodule

module adffn
    ( input d, clk, clr, output reg q );
    initial begin
      q = 0;
    end
	always @( posedge clk, negedge clr )
		if ( !clr )
			q <= 1'b0;
		else
            q <= d;
endmodule

module dffsr
    ( input d, clk, pre, clr, output reg q );
    initial begin
      q = 0;
    end
	always @( posedge clk, posedge pre, posedge clr )
		if ( clr )
			q <= 1'b0;
		else if ( pre )
			q <= 1'b1;
		else
            q <= d;
endmodule

module ndffnsnr
    ( input d, clk, pre, clr, output reg q );
    initial begin
      q = 0;
    end
	always @( negedge clk, negedge pre, negedge clr )
		if ( !clr )
			q <= 1'b0;
		else if ( !pre )
			q <= 1'b1;
		else
            q <= d;
endmodule

module top (
input clk,
input clr,
input pre,
input a,
output b,b1,b2,b3
);

dffsr u_dffsr (
        .clk (clk ),
        .clr (clr),
        .pre (pre),
        .d (a ),
        .q (b )
    );

ndffnsnr u_ndffnsnr (
        .clk (clk ),
        .clr (clr),
        .pre (pre),
        .d (a ),
        .q (b1 )
    );

adff u_adff (
        .clk (clk ),
        .clr (clr),
        .d (a ),
        .q (b2 )
    );

adffn u_adffn (
        .clk (clk ),
        .clr (clr),
        .d (a ),
        .q (b3 )
    );

endmodule