Atari ST series Technical Reference Manual page 374

T h is c o m m a n d s e t s t h e d a t e a n d ti m e f o r t h e i n t e r n a l t i m e - o f - d a y c lo c k .
T h e v a l u e s a r e p a s s e d in p a c k e d B i n a r y C o d e d D e c im a l (B C D ) f o r m a t . T h is
m e a n s t h a t e a c h n ib b le c o n t a i n s a n u m b e r f r o m 0 - 9 , s o t h a t e a c h b y t e
y i e ld s a t w o - d i g i t d e c i m a l n u m b e r . A n y d i g it t h a t i s n 't in B C D f o r m a t is
t r e a t e d a s a f la g i n d i c a t i n g t h a t t h e c u r r e n t v a l u e s h o u l d n 't b e c h a n g e d .
Input parameters
Byte
Number Description
1 Y e a r ( l a s t t w o d i g it s o n l y )
2 M o n t h
3 D a y
4 H o u r s ( 0 - 2 4 )
5 M i n u t e s
6 S e c o n d s
366
APPENDIX I
$1B Set Time-of-Day Clock