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發表於 2010-10-20 14:31:16
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reg [7:0] RxD_data;
1 i, k6 P8 d- q8 K% p3 y6 greg [7:0] RxD_data_out;7 g9 j! c/ F" I! I: g
always @(posedge clk) begin$ X9 W! y4 w7 P! a- q
if(Baud8Tick && next_bit && state[3]) begin 1 ]+ l% g7 a/ p7 _$ m5 k4 V6 ^
RxD_data <= {~RxD_bit_inv, RxD_data[7:1]};& h3 s/ Q& y0 W8 F: ^. q3 d, t
end9 C6 A! S( v9 \& D
if (Baud8Tick && next_bit && state==4'b0001 && ~RxD_bit_inv) begin! y4 W3 _; X) S3 g& E
RxD_data_out <= RxD_data;
$ h$ E/ S- A9 m& S7 V end
# x5 u5 C* j5 ^. rend% q" Z* }# m/ x" i9 n* D# T+ c8 j* N
% l: R, F( H) [6 k0 s) O
4 Y# i1 ^8 I& L, p5 Ureg RxD_data_ready, RxD_data_error;
; q. K8 o9 C2 n2 A7 wreg RxD_data_ready_in;
" Q# n1 }& w" m- E4 ?reg[0:2] count;! U" }# P1 I+ l; ~
reg[0:2] count2;
+ x# N+ D/ D' b5 ], wreg count1;
- ?% p1 }$ C2 r6 H) balways @(posedge clk)9 t1 |; y+ f* @9 n
begin! s) P3 Z9 f0 O( U) d* S% Z, D
: ^) N5 p2 e! d9 A2 j( A
if (Baud8Tick && next_bit && state==4'b0001 && ~RxD_bit_inv) begin0 k! D; O: G* V4 `9 G3 v8 o
RxD_data_ready_in <= 1'b1;0 ]0 @" Y& [2 z( Y9 J. G
count1 <= 1'b1;
4 M5 H1 U- {2 e" f count <= 3'b000;
7 w; o# k. |# g8 y0 K& j count2 <= 3'b000;
" Q) W+ P# I5 b0 w end 9 P, H$ W; `: p u
else if(count==4 && count1==1 )begin
' N) _6 M* N! ?6 p+ C RxD_data_ready <= 1'b0;) W- V; U5 K9 ]0 X0 _9 L: D& r
count <= 3'b000;
6 m+ i) S1 L# c/ L% d6 @ count2 <= 3'b000;
/ Z+ r2 D: Y; h) ]. q( \' v count1 <= 1'b0;
3 A: ]+ t0 E- i0 A end
' k y3 @* u0 o# Y' M" } else if(count2==4 && count1==1 ) begin4 e: `' [( K" m1 F6 f
count <= count+1 ;& N9 N4 K1 X7 \( R! C
RxD_data_ready <= RxD_data_ready_in ;
6 R% @# l% D& W2 I! P end2 c4 `6 n ^8 Z/ ]+ ]4 B
else begin& N+ G' ]5 K6 r2 N2 ^, P) W0 L( r A
count2 <= count2+1 ;% \+ @ G; c/ \+ A6 }0 {2 q
RxD_data_ready <= 1'b0;
y7 x. v5 }: S end
' ^7 S* c/ Y1 o# T( y RxD_data_error <= (Baud8Tick && next_bit && state==4'b0001 && RxD_bit_inv); // error if the stop bit is not received. Q# G2 r$ Z! T" h
& b3 q, y- m) [2 q
end
; {% U f0 w5 @) M. ^) F6 `- ?8 O& a# y
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. I1 }8 f( p* W# Oreg [4:0] gap_count;
# n% P% `) X5 ^- E# p4 Z+ palways @(posedge clk)
$ O0 T- u* h' Q9 F/ B1 ^ if (state!=0)
2 \ \( d( o9 }% E2 |# y$ s- b! c gap_count<=0; + w* p2 X. @+ S5 W y' y
else if(Baud8Tick & ~gap_count[4]) & s5 V3 a4 t# _4 [/ q% M
gap_count <= gap_count + 1;$ K9 v9 v' F! L5 ?( W
assign RxD_idle = gap_count[4];, P4 w( Q3 n1 i9 d& S" c8 @" x# P
reg RxD_endofpacket; 0 |, b- C( N6 j! Z$ `
always @(posedge clk)
+ O. E% n9 c7 a/ t9 U gRxD_endofpacket <= Baud8Tick & (gap_count==15);; z3 u* o1 B7 _, B! O
: ]) S( Q3 ? E+ l0 W2 \! u8 c# M
endmodule- _- L! Z' s3 c7 F! D
8 V7 U, N5 d: e# M- h0 ?4 m
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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