DP-1100B II| DP-1100B II
Since t h e u n i t has m a n y f u n c t i o n k e y s , a 6 x 4 m a t r i x h a d
been m a d e in o r d e r t o m a k e t h e best use of t h e i n p u t / o u t
p u t p o r t s of IC1 ( 4 - b i t m i c r o p r o c e s s o r ) . T h e key i n p u t c a n
be j u d g e d by key s c a n n i n g pulses f r o m IC1 (6 lines in t i m e
division) a n d f o u r key i n p u t lines.
Pin 11 to 1 6 of IC1 are p e r i o d i c a l l y p r o v i d i n g t h e pulses
s t a g g e r e d by a regular t i m i n g as s h o w n . Each of t h e m
enters t h e v e r t i c a l line of t h e key m a t r i x t h r o u g h a d i o d e ,
w h i c h p r e v e n t s m o r e t h a n 2 keys f r o m b e i n g pressed at
t h e s a m e t i m e . Pin 2 6 t o 2 9 are i n p u t lines a n d t h e y are all
0 V w h e n no keys are p r e s s e d .
For e x a m p l e , w h e n t h e PLAY key is p r e s s e d . T h e pin 1 4
line a n d pin 2 6 are s h o r t e d , a n d s c a n n i n g pulse f r o m pin
1 4 is i n p u t t o pin 2 6 .
IC1 ( 4 - b i t m i c r o p r o c e s s o r ) r e c o g n i z e s t h a t t h e PLAY key
has b e e n p r e s s e d , b a s e d o n t h e i n p u t t o pin 2 6 a n d t h e
t i m i n g of pulse at pin 1 4 a n d gives t h e PLAY i n s t r u c t i o n to
IC15 ( c o n t r o l m i c r o p r o c e s s o r . )
T h e reason t h a t t h e t i m i n g pulse has a d o u b l e f r e q u e n c y at
pin 1 6 is t h a t t w o c l o c k signals are e n t e r e d s i m u l t a n e o u s
ly, w h e n M - R E A D a n d CLEAR keys are pressed at s a m e
t i m e .
F i g . 1 - 5 - 1 6 - 2 1C1 T i m i n g P u l s e W a v e f o r m
5 5
F i g . 1 - 5 - 1 6
1. CIRCUIT DESCRIPTION
1 - 5 - 1 6 . K E Y D A T A A N D T I M I N G P U L S E O P E R A T I O N
Summary of Contents for DP-1100 B
Page 3: ...D P 1 1 0 0 B II D P 1 1 0 0 B II I BLOCK DIAGRAM ...
Page 32: ...D P 1 1 0 0 B II 1 CIRCUIT DESCRIPTION Disc Scratch Dust RFES D C O N D O C K Fig 1 2A 3 5 ...
Page 112: ...2 IC OPERATION OF EACH CIRCUIT AND D P 1 1 0 0 B II PIN DESCRIPTION Fig 2 4 1 G 1 ...
Page 117: ...DP 1100B II I OPERATION OF MAIN MICROPROCESSOR Fig 3 1D Q data reading flow chart ...