Bally 5000 Plus, Manual

Page: 107 / 388

3 . MPU BOARD
C i r cu i t Des c r i p t i on ( cont ' d )
MPU " T EST " bu t t on
P r e s s i ng t he " T E S T " but ton c l oses
t h e test sw i t c h wh i c h I nput s a
s i gna l t o U29 a t p i n 40 . So f t wa r e
r e cogn i z es t he s i g na l a n d p e r f o r ms
t h e d i agnos t i c t e s t .
T h e numbe r o f
t i mes t h e bu t t on i s p r e s se d
de t e r m i nes t h e spe c i f i c d i agnos t i c
t es t .
Sound code
The s i mp l e
I n t e r f a c e s
u s e d on l y
boa r d .
CB2
sound ou t pu t ,
w h i c h
w i t h t he b a c k p l a ne , I s
I f t he r e i s no sound
P i n
1 9
T e r m i na t e s
P 2 p i n 1 2A
To enab l e I n t e r f a c i ng w i t h t he
sound boa r d , U29 p i n 39 sends t he
sound boa r d I n t e r r u p t ( SB I ) s i gna l
t e r m i n a t i ng a t P 2 p i n 1 B . T h e
fo l l ow i ng s i gna l s con t r o l t he sound
boa r d .
P i n T e r m i na t e s
PAO
2 P 2 p i n 1 C
PA1 3 P 2 p i n 2C
PA2 4 P 2 p i n 3C
PA3 5 P 2 p i n 4C
3-50
NOT E S