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基于FPGA的DAC0832电路的驱动代码7 R, B' F% G1 g& c
, d$ x+ T$ z) G
原理图 D& Y ^" h2 [( R
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时序:
2 W* G+ c% l6 ^7 [6 ?![]()
" u, T6 e$ f( ?6 Q% B这里的时序我分为 CS 拉低,WR拉低和赋值。WR拉高,CS拉高 4个阶段,6 }' j( h5 j2 R& s3 D- Y5 j
代码:5 Z) R, w( c- b) p- j! i. {
module dac
+ ]+ H8 m' ]1 X2 Z# B$ L* r (
& m6 i! U" M' F2 _/ w7 U; s sys_clk,reset_b,- ~3 m$ }. a# ~+ F
wr,cs,data0 L2 p/ {0 @9 s/ W/ D
);
3 H6 t! j1 g1 M. ]& C8 F input sys_clk,reset_b;
$ Q0 ?- E& i( g output [7:0] data;
* i5 b( f! p2 X+ x( { output wr,cs;
0 P5 z, L$ j ]3 G; A3 d/ i) ?: C
7 Z. {5 w0 C0 L" D reg wr,cs;
# M, P" l- M$ F- ~ reg adc_clk;
0 g, X/ q5 f4 p/ [9 t reg [7:0] data,data_buf;
& n5 q' k. a; ~( Q' i: p, e reg [2:0] next;
& E; ~8 d& ~' N
' z$ A2 B' v. g5 o/ g parameter state1 =3'd0;6 f; \# \/ B* j }1 ]: K5 k+ K
parameter state2 =3'd1;2 F5 g- C `1 k' G: a
parameter state3 =3'd2;" X; w8 S# t9 q3 c: m
parameter state4 =3'd3;- L! F! k7 b! l* Q3 C
reg[15:0] count;9 ]# B% [( C$ C% w
always @ (posedge sys_clk)
: d( \0 v- w8 X# W4 F begin- T: m% c6 }* q$ u# X& T
if(!reset_b)
+ R4 P) m- S+ j6 q8 q" [ begin
- T$ t B8 e( @4 a' V1 u% C count<=16'd0;6 R5 S% i3 W3 y" ]' d( }. `- e8 }: `
adc_clk<=1'b1;
& I# W6 w" y6 H- O end
. O! e* G1 r- e. e else
/ ?8 Y) B F% `# m/ h/ p# Z if(count==16'd100)1 k$ }' T$ t+ k. e" {2 X
begin5 y- I# k7 s3 a8 I( H+ l
count<=16'd0;3 `6 a+ Q( W1 Y. t y4 |! F
adc_clk<=~adc_clk;# x. ]& ]! c7 t8 a! v
end1 P" L( G. I/ W, u6 Z# Y- ^
else count<=count+1'b1;
! p! s2 e. a0 c0 V) L* s end- u+ q- n8 x0 u1 p5 O
//=========data buf add=================, H" S8 p+ _7 ~4 D, s7 j5 s. d
reg[20:0] count_adc;
, N' Q3 I. B# c$ ?, H+ U, ] always @ (posedge sys_clk)1 F# t) v) j% M: K
begin
6 R& {8 T0 H6 H# ]* K/ [: g5 s if(!reset_b)
0 d7 W0 a4 `% W/ s% E* j" { begin. P) l# u: R7 ?
count_adc<=21'd0;
: X0 D, k- e$ J' g, [) d0 \ data_buf<=8'b0;1 ^' P I* u( d9 X2 _2 W! z# c
end
5 _2 P' _6 p8 w% c else
* S! @! b8 k8 R4 q- c if(count_adc==21'd50000000)
3 n0 ?; j5 R0 C! d5 R. I: z, f begin1 q! V. V9 g' k, s+ J1 V
count_adc<=21'd0;
1 v0 I, h. D7 h4 ^$ ]% R data_buf<=data_buf+1'b1;
7 T! |* N' Z/ V( J end4 S. O+ A U0 l% C$ A$ ^. h
else count_adc<=count_adc+1'b1;2 l* B4 Z3 L6 A8 ~$ J' W& N5 R# y
end
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always @ (posedge adc_clk)
4 W7 Q+ H# c* T( U) Z begin8 V' y y+ b N6 q" h
if(!reset_b)
" D7 B' t+ k0 c7 ^; j# M& A begin
5 [8 H4 f+ M* O$ r# \9 |9 q( e next<=state1;2 m8 I7 J# l% {) J) |
cs<=1'b1;4 @6 j' j6 _- Y* E3 u+ N# L+ _
wr<=1'b1;- a7 |% G1 h' r! m" @; [
end
- T6 j5 C) {, i y" E else
& }% c8 Q* v4 A2 ^1 i" Y6 ^- A case (next)
# A! `6 `9 P% B, U: i state1 :
' {5 [! A. V8 Y$ B, ^8 b' t' J begin/ ?1 `* [1 P8 \; ~3 k
cs<=1'b0;/ t0 ~' I+ E" n5 ^8 p+ \( `5 z
next<=state2;3 j; N. b2 U' g* s! m
end
3 k4 Z+ q/ l1 h* T1 `, X state2 :
6 D% B( v7 ]. \0 z; J3 \/ z begin
* ]: k' z( U- |$ T wr<=1'b0;
) e/ u& I, w8 T- H. R( B- L. g data<=data_buf;
8 K* D6 N, F, T8 E* u9 v next<=state3;4 B' w4 k# O+ ~8 }0 |$ Z0 o
end
) K* z+ J/ c. K. A* g) a state3 :
' I& }4 ?3 P* X9 v& ]/ H- S begin2 k$ A d) c7 {) Y
wr<=1'b1;8 d( }) O9 l3 k8 p, h, z
next<=state4;# y: h( l" S3 H( U% Z2 ]& D
end- k; U( d3 W* l5 V$ y
state4 :+ }2 _5 N* R5 ^' A
begin( P' Q' @7 r9 Y( a6 M6 J, t! b
cs<=1'b1;
2 V5 u! @; m0 e. `0 w( Z& z2 {- U next<=state1;. { {( \7 M# D& C/ O; B3 [
end N1 y6 A1 b9 q5 [+ @7 A
endcase/ m. R2 j1 ^% M+ D
4 ?: x. c5 Y$ e- |% q
end- ]+ w0 |; Y% r( g- d: r
" }& }! e( ^; K# |! A. r0 [& J% e8 _: h9 ^
3 J( P0 @4 W5 ?0 r3 ? I/ tendmodule
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