Intel MCS48 User Manual page 392

8291
Appendix
A
MODIFIED STATE
DIAGRAMS
Figure
A.1 presents
the interface function
state diagrams.
It
is
derived
from IEEE
Std. state diagrams, with the
following changes:
A. Controller function omitted.
B.
Addressing
modes
included
in
T,L
state
diagrams.
Note
that
in
Mode
3,
MSA,
OSA
are generated only
after
secondary address
validity
check by
the microprocessor
(APT
interrupt).
C.
All
remote messages
sent true
in
each
state
are
indicated.
D.
All
remote
multiline
messages decoded
are condi-
tioned by
ACDS. The
multiplication by
ACDS
is
not
drawn
to simplify the diagrams.
E.
The symbol
e
indicates:
1.
When
event
X
occurs, the function
will
return to
state
S.
2.
X
overrides any other
transition
condition
in
the
function.
Statement
2 simplifies the diagram, avoiding
the
explicit
use
of
X
to condition
all
transitions from
S
to other
states.
SH
|
ATN+
F1
(WITHIN
t
2 )
F1 =
TACS
+ SPAS
I
J
THIS TRANSITION WILL NEVER
OCCUR UNDER NORMAL
OPERATION.
F2 -
ATN
+
LACS
+
LADS
F3 =
ATN
+ rdy
T3'
= T3
•
CPT
•
APT
Figure
A.1.
8291 State
Diagrams
(Continued
next
page)
8-102
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