Bally 5000 Plus, Руководство пользователя

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3 . MPU BOARD
C i rcu i t Descr i pt i on ( cont ' d )
I n t e r r up t Cyc l e
T h e I n t e r r up t
m i c r op r ocessor
r eque s t i ng a n
m i c ro p r ocessor
cyc l e I s
per i phe r a l
I n t e r r up t
a c t i on .
a 68000
dev i ce
o f
t he
The c h i p sends a n I n t e r r up t s i gna l
s i mu l t aneous l y t o :
( 1 ) t he s e l e c t o r / l n t e r r u p t ( U 1 0 1 ) .
T hen , U 1 0 1 p i n 1 7 sends a
va l i d per i ph e r a l
add r e s s
( VP A ) t o t he m i c r op r ocesso r
( U 1 p i n 2 1 ) .
( 2 ) t he p r i or i t y encode r ( U9 ) .
The
T h e n , U9 de t e r m i nes t he
h i g h e s t p r i o r i t y I n t e r r up t
r eque s t a n d sends t he l e ve l
I n t e r r up t t o t he m i c r o­
p r ocessor us i ng t he I n t e r r upt
p r i or i t y
l eve l l i ne s a s
fo l l ows .
I P LO U1 p i n 25
I P L 1 U 1 p i n 2 4
I P L 2
U 1 p i n 2 3
m i c roprocessor sends I t s
func t i on
s t a t us t o U 4 2 us i ng t he
func t i on code ou t pu t l i ne s a s
fo I l ows .
FCO U 1 p i n 28
FC1 U1 p i n
27
FC2
U 1 p i n 26
U42 p i n 6 sends t he l ACK s i gna l t o
U 1 0 1 p i n 4 .
When t he m i c r op r ocessor r ece i ve s
t he l eve l I n t e r r up t a n d t he VPA ,
t he 68000 m i c rop r ocessor beg i ns
e x cept i on p r ocess i ng ( 68000
m i c r op rocessor f o l l ows a spec i a l
p r ocess cor r espon d i ng t o a spec i f i c
user o r a u t o vec t o r numbe r ) .
The m i c r op r ocessor s i gna l s t he
l e ve l I n t e r r u p t t o U 1 0 1 on a d d r e s s
l i ne s , A 1 ( p i n 1 ) , A2 ( p i n 2 ) , a n d
A 3 ( p i n 3 ) .
3-20
NOT E S