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4#
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發表於 2010-10-20 14:31:16
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reg [7:0] RxD_data;
& k& N9 j8 {0 Rreg [7:0] RxD_data_out;
6 ?4 V# C3 K3 b5 f) K* k8 Y3 Qalways @(posedge clk) begin
! {8 X5 p4 W+ O4 \ if(Baud8Tick && next_bit && state[3]) begin & b0 J4 J6 t" i/ h
RxD_data <= {~RxD_bit_inv, RxD_data[7:1]};" R+ ?1 L, [# l! i9 D$ q0 E( I' n
end, a; T0 j9 z1 f4 M( z/ k
if (Baud8Tick && next_bit && state==4'b0001 && ~RxD_bit_inv) begin
+ b( h4 x$ `7 K RxD_data_out <= RxD_data;9 M' f$ H, l3 W! l% G' w( f
end
6 D" b( B; V6 B( n5 C6 Kend
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, T) K0 j( R J+ \: `- i9 wreg RxD_data_ready, RxD_data_error;
0 g2 I4 G8 l7 Areg RxD_data_ready_in;8 c3 j; e: X) {6 X: I+ C8 Y! f
reg[0:2] count;
0 K$ E% A, Z/ ^, e% ^9 g4 A# C* _reg[0:2] count2;' `: _' M' ~& i5 D
reg count1;
+ k# h0 r+ S) i" h% H$ o Ualways @(posedge clk)( \6 ~' v4 A4 v" K0 y6 ?$ `6 G
begin; ^" M5 k6 Y5 K9 K/ h
; \! K( y# B6 p) C! ? if (Baud8Tick && next_bit && state==4'b0001 && ~RxD_bit_inv) begin
8 {& g9 Q1 t$ ] RxD_data_ready_in <= 1'b1;) F7 _( j5 F/ g7 Y# ^( g! v
count1 <= 1'b1;
1 |$ Y1 F; d( R( k" e6 d count <= 3'b000;7 Q. |4 s( L- L8 k. V
count2 <= 3'b000;
' P: m7 X ~8 T V% b' T1 { end 8 P3 G, h3 n# s: I' W; v
else if(count==4 && count1==1 )begin" k0 Z. A; N7 C3 e. g, y
RxD_data_ready <= 1'b0;) ~% h& ^9 J/ \- L6 E) y
count <= 3'b000;" k; N* r D' j: R
count2 <= 3'b000;
6 m6 x3 d% N: L0 [( ] count1 <= 1'b0;
7 ]# t7 i# l5 L: q$ o6 d! n end
! Q% V9 D1 S! w* Q, o9 ?# A6 S4 C else if(count2==4 && count1==1 ) begin! b: Q, r( S- i! F7 I
count <= count+1 ;
- Z0 R6 @% Y* ^- | w2 D _4 o RxD_data_ready <= RxD_data_ready_in ; w M$ {: ?( B
end0 Q) y. G% @8 U1 f. [
else begin4 G ~6 u7 p/ D9 ]9 i. ]9 @
count2 <= count2+1 ;3 Y U$ |' A) a
RxD_data_ready <= 1'b0;8 j, L% Z' Z1 y2 n: R
end
' I& R- z3 r6 J# f. k9 ]) V' @ RxD_data_error <= (Baud8Tick && next_bit && state==4'b0001 && RxD_bit_inv); // error if the stop bit is not received4 f' }, x |5 Q: f' U& s- v
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end, m6 `# }8 b2 l S/ b
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reg [4:0] gap_count;3 V% |7 y K) O9 |; k4 f
always @(posedge clk)
2 J }3 N" z6 V6 Z6 y if (state!=0) ) ]0 j% b5 \7 z! k
gap_count<=0;
! Z2 C; v& B# h; m" U$ O" l else if(Baud8Tick & ~gap_count[4]) # q$ g& _9 W9 ~5 [9 L
gap_count <= gap_count + 1;; W" j3 v* m" V( m
assign RxD_idle = gap_count[4];
+ y# R! J( y1 v' ~$ x) Freg RxD_endofpacket;
5 X5 V3 N" [% f1 S6 K1 Walways @(posedge clk)
4 u6 q( Q1 F/ v* hRxD_endofpacket <= Baud8Tick & (gap_count==15);
O! u& Z; k, z9 y9 m J8 W: k% D! }! G
endmodule2 V7 A, [9 j- x5 X4 s
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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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