Figure B-12 Sine Wave Generator-Second Order Oscillator - Motorola DSP56800 Manual

B.1.13.2 Second Order Oscillator
Figure B-12 gives a graphical overview of a second order oscillator.
a = Stored initial value which
is the desired tone amplitude
Figure B-12. Sine Wave Generator—Second Order Oscillator
opt cc
clr a
move #$4000,y1
move #$6d4b,y0
move #$1,r1
move #tmp,r0
move #0,n
do x0,loop2
mac -y1,y0,a
neg a
mac y1,y0,a
move
tfr y1,a
loop2
move
;
;
a
–
T
x0 = 2*cos( 2π Fs/F0)
F0 = Oscillation Frequency
Fs = Sampling Frequency
; 1
; 2
; 2
; 1
; 1
; 1
; 2
; 1
y1,x:(r1)+n ; 1
; 1
a,x:(r0)+n ; 1
x:(r0)+n,y1 ; 1
y1,x:(r1) ; 1
______
Total: 16
DSP Benchmarks
x0
sin(w t)
0
T
1
2
2
1
1
1
3
1
1
1
1 temp storage for swap
1
1
5N+12
AA0090
B-21