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發表於 2010-10-20 14:31:16
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reg [7:0] RxD_data;
$ N y( U# K: g( M- A) ~reg [7:0] RxD_data_out;
! `) `6 K, C: ^/ Z4 N# G( ^always @(posedge clk) begin
0 Z' P8 T+ h' }1 o9 F8 ? if(Baud8Tick && next_bit && state[3]) begin
2 O# F) R$ f0 C5 c' q7 q, n RxD_data <= {~RxD_bit_inv, RxD_data[7:1]};
# T: P0 l; ^* J* r8 H9 [1 _ end1 X+ K* e# B3 h
if (Baud8Tick && next_bit && state==4'b0001 && ~RxD_bit_inv) begin
. k& o( g: G4 l+ d RxD_data_out <= RxD_data;
+ t. G6 f% {# ^& L end
* o8 x$ _5 ? A* [, G2 i. l" @1 b( cend" k. `# m& ~2 O8 a6 b# y
; J, l, a# ]6 M- h, u- i, s2 F z% I4 P! s H# `
reg RxD_data_ready, RxD_data_error;
% l/ _, z: h3 t( c' J8 x2 _6 r5 ereg RxD_data_ready_in;
: Q9 X T8 _+ B Preg[0:2] count;
$ w [' T3 H4 ?3 x) rreg[0:2] count2;
9 B) _2 P) p) @$ z! O5 Hreg count1;
. W" |8 b) A0 `- u9 H/ Oalways @(posedge clk)8 m3 B4 k. j2 _' H
begin
4 i, r9 O1 P; t! [) T5 L) m% c0 o' ^" {" c4 n; w
if (Baud8Tick && next_bit && state==4'b0001 && ~RxD_bit_inv) begin$ w; Z s; n5 }6 a. ~
RxD_data_ready_in <= 1'b1;
3 ~5 z2 s2 {3 [7 ]" A count1 <= 1'b1;" Y0 e( U9 z& E4 J
count <= 3'b000;. d7 K* { O K
count2 <= 3'b000;
8 M5 j8 [/ K* O2 C& x end
) l9 x5 P- q$ p else if(count==4 && count1==1 )begin- Y! I* `) Q( H) D1 l
RxD_data_ready <= 1'b0;; V, o' U; c# Y$ D
count <= 3'b000;
2 C3 `0 g6 v* P count2 <= 3'b000;2 f% Q$ {0 @: N- L
count1 <= 1'b0;* T2 Q1 _3 x% x- `/ y0 g
end
/ K5 h' e8 F' H# r9 M else if(count2==4 && count1==1 ) begin1 ^! H7 ?! `" [" j5 o
count <= count+1 ;3 M, L- F f0 D
RxD_data_ready <= RxD_data_ready_in ;6 U. {! o+ [3 o4 v' I7 ^
end: K5 \- c- Y. I
else begin4 H# g- L+ `/ K7 p
count2 <= count2+1 ;3 [2 W6 h2 H* A, k! k- G
RxD_data_ready <= 1'b0;+ c( m8 T; n- [* W6 g
end
/ `8 g3 X1 y! x RxD_data_error <= (Baud8Tick && next_bit && state==4'b0001 && RxD_bit_inv); // error if the stop bit is not received
1 u# C* ]4 i* K8 ~8 J. T) Z5 v3 Y+ ?7 G( |' N
end$ M8 H% s( ]$ c5 @
$ f; d" B- e8 b* C1 A' `& {2 w' J' p3 A) ]
9 P5 ?/ d. j4 ?/ W9 Qreg [4:0] gap_count;
* j: n8 q: f) U7 o calways @(posedge clk) $ R6 G; N4 ^. u1 t- [* H
if (state!=0) - w! y+ T; o: Q z V2 n
gap_count<=0; Y* J6 s' W- g
else if(Baud8Tick & ~gap_count[4]) ' A+ S8 k Q/ L* q
gap_count <= gap_count + 1;
8 C6 A, O+ a! wassign RxD_idle = gap_count[4];
# f/ J* F! E( r& A1 K/ vreg RxD_endofpacket; , E6 w! Y6 I, {7 Y; d5 {
always @(posedge clk) : J* _, R. p) u
RxD_endofpacket <= Baud8Tick & (gap_count==15);$ X3 s: z- V" N& q
& G# N: q6 N& Y: N* y
endmodule* L e3 d$ X" a( w/ x( [
: \7 T3 J& \: Z! K4 @) ?* F
我想知道為什麼RxD_data_ready腳在資料錯誤時還會拉成high,麻煩會的高手教教我,謝謝! |
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