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發表於 2009-6-11 12:43:50
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ODDR2 #(
/ I1 z$ G# E+ i+ H, M .DDR_ALIGNMENT("NONE"), // Sets output alignment to "NONE", "C0" or "C1"
) B( l; e5 e ?* r0 x) i, X .INIT(1'b0), // Sets initial state of the Q output to 1'b0 or 1'b11 I/ V. I; ~8 Z5 W9 z {/ N
.SRTYPE("SYNC") // Specifies "SYNC" or "ASYNC" set/reset
5 Z9 }! w S Q( h) @ ) ODDR2_inst () F1 \' `& ~0 P3 D
.Q(oVGA_CLOCK), // 1-bit DDR output data, w4 f) F* x$ R6 e+ G; b3 Y$ x
.C0(clk), // 1-bit clock input
1 E4 t: w: g" m. L+ G .C1(~clk), // 1-bit clock input
, L; d8 e$ s& c: Q .CE(1'b1), // 1-bit clock enable input
/ n' @. j8 _* I! ` .D0(1'b0), // 1-bit data input (associated with C0)
9 r. E" e8 i' l3 m, ] .D1(1'b1), // 1-bit data input (associated with C1)
5 T; L/ M. c" x+ t' {9 R# _) D5 M, m% x .R(1'b0), // 1-bit reset input6 y8 x3 U; h6 Z
.S(1'b0) // 1-bit set input) F& o% _; s4 n* p: _
);
2 {8 n7 g0 Q( H/ a# I }
; o5 f8 ~2 i5 ]& F5 M: g% Y) z% F8 Q: Kalways @(posedge clk)
, Z1 k+ `/ G1 P8 g: Lbegin: P1 ]7 r' W7 `( D; D
oVGA_SYNC <= oRequest;3 |! w' D! q: C& X- i
end ( T: F! L l# B9 V( }, t
2 K9 ]8 T1 ]1 V: zalways @(posedge clk)2 u5 S e- v" {1 H* J/ Y8 R
begin
- g) v9 N/ X' C, F8 W6 i, y if (rst)
5 G8 a1 z) v2 L! j oRequest <= 1'b0;8 M3 f6 Z. \. t) y5 i" t# w
else begin
0 `0 r% }# [0 T) O8 h3 J$ l if (h_cnt >= (X_START-2) && h_cnt< (X_START+H_SYNC_ACT-2) && v_cnt>=Y_START && v_cnt<(Y_START+V_SYNC_ACT))
4 m: g2 w" G% l& G% i; ]# c+ a oRequest <= 1'b1;
3 M# I- ?- w* ?8 z else+ s: \2 l a ?* J
oRequest <= 1'b0;
# w* h! a5 n" l. ?" Z end
2 Z# P4 Q3 D( A$ ^* F0 @9 K( C; bend( e2 Q& b* G8 P. v( I' Z
' T+ D) y" n) F2 k% \, G* b
// H_Sync Generator, Ref. 25.175 MHz Clock
" v* ?# Q# V" palways @(posedge clk), e3 B" b9 F; M6 \) R
begin5 H. z. k' D" P/ s* j
if (rst) begin; }, K% L ~" |4 c5 C* l3 ]+ [( h
h_cnt <= 12'd0;' ?0 z9 [% U8 c, P
oVGA_H_SYNC <= 1'b0;! x" E/ Z# F2 J" y
end
! y5 Q4 d4 ~* p else begin
6 y- {6 \1 Y- d p. g // H_Sync Counter
: v6 a7 e* V5 ? if (h_cnt < (H_SYNC_TOTAL-1) )! d* y1 l9 ~$ O7 u' O3 Z: ~1 Z
h_cnt <= h_cnt + 12'd1;
8 O% b5 \# M4 C1 O+ g- _" E: y else/ [0 c6 ]) h# {; b: I! z
h_cnt <= 12'd0;7 j# a5 E" N" w2 r& c$ k' G: f
% h, B0 a/ K/ h. b3 T
// H_Sync Generator0 Q6 U" w: m: _" Q
if( h_cnt < H_SYNC_CYC ): s0 a6 d6 g) g( _4 P$ }
oVGA_H_SYNC <= 0;
" e! w& t! `, P( E else
' }: W l: a/ n: t; S1 V I oVGA_H_SYNC <= 1;
, o: q2 g9 r( B, S% F% j+ A3 Y7 x! o end
! t4 M& ^1 x' U# z* \1 lend
7 C; v2 |5 P( @6 \$ N$ ?6 b i# f& `9 y1 N5 t! v; f8 V
always @(posedge clk)
( j6 [% V. f jbegin
' p) u m* }5 E7 E) w) c if (rst) begin+ D& p, _) l+ Y3 k X H b1 v6 t
v_cnt <= 12'd0;5 M6 Z3 i" S' x+ G$ C4 \# b
oVGA_V_SYNC <= 1'b0;
' I7 M$ T; s3 l z2 C3 S end" G. b, |- E- e1 |% [7 F$ U. N
else
% [0 L L: e; c1 B \" t+ x1 B if (h_cnt == 0 )) C+ M2 y1 S: q/ m6 j
begin0 z5 e* @8 d0 m' O) L
// V_Sync Counter( V/ g' z: e+ g7 M4 u5 Y
if (v_cnt < (V_SYNC_TOTAL-1))
' l7 Y5 ~, ^3 q( W7 t* ~1 x5 w' t v_cnt <= v_cnt + 12'd1;
0 T+ D7 g; Y9 H1 W/ e; E- _ else
: p3 ?* ? ~8 B5 o8 P v_cnt <= 12'd0;
# A6 T& Q! e6 W) p2 M. I // V_Sync Generator3 X" N3 ?# N( a9 Y. I& W
if (v_cnt < V_SYNC_CYC)6 _. L$ b* s' x; _# K
oVGA_V_SYNC <= 1'b0;
' n+ r0 E2 Z) t else
3 w3 L& [0 O* n0 z3 v) M oVGA_V_SYNC <= 1'b1;
1 }9 F8 o0 Y. @ r& v7 ~ end
6 N k5 i0 @! |* _( iend6 k" H3 o+ X- U& |8 h% P, }( e
% B# M0 q' x9 K" W
a p7 G. m' \* C8 hendmodule |
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