Atari ST series - Page 231

Xbtimer
Set an MFP Timer
Xbtimer() Opcode = 31
T h e X b tim e r() fu nction allow s y o u to se t th e M FP tim e r re gisters a n d a s
sign an in te rru p t v ec to r to a tim er.
C macro format
in t tim e rn u m , co n tro l, d a ta ;
lo n g v ecto r;
X b tim er(tim e rn u m , co n tro l, d a ta , v ecto r);
Machine language format
m o v e.l v ec to r, - (sp)
m o v e.w d a t a ,- ( s p )
m o v e, w co n tro l, - (sp )
m o v e.w tim e m u m , - (sp)
m o v e .w # 3 1 , - ( s p )
trap # 1 4
ad d .l # 1 2 ,sp
Inputs
v ec to r lo n g T h e a d d re ss o f th e in te rru p t h an dler ro u 
tin e a sso cia te d w ith th is tim e r,
d ata w o rd T he v alu e sto re in th e tim er d ata register,
co ntro l w o rd T h e 8 -b it v alu e to p la ce in th e tim er's
co n tro l reg iste r.
F o r T im e rs A a n d B , th e v alu es a re:
Control Value Timer Mode
0 T im e r off
1 D ela y m o d e, clock d ivid ed b y 4
2 D elay m o d e, clo ck d iv id ed b y 10
3 D ela y m o d e, clo ck d ivid ed b y 16
4 D elay m o d e, clo ck div id ed b y 50
5 D ela y m o d e , clo ck d ivid ed b y 64
6 D e lay m o d e , clock d ivid ed b y 100
7 D ela y m o d e, clo ck divid ed b y 20 0
8 E v e n t C o u n t M o d e
9 P u lse L e n g th m o d e , clo ck divid ed by 4
10 P u lse L e n gth m o d e, clo ck d ivid ed b y 10
11 P u lse L e n g th m o d e, clock divid ed b y 16
12 P u lse L en g th m o d e, clock d ivid ed b y 50
13 P u lse L e n g th m o d e, clock d ivid ed b y 64
14 Pu lse L en gth m o d e, clock d iv id ed b y 100
15 P u lse L e n g th m o d e, clock d iv id ed b y 2 0 0
223