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*
Maskable
Non
Interrupt
A
negative
edge
be
generated.
sequence
by
the
program,
interrupt.
*
Request(FIRQ)
Fast-Interrupt
A
Low
level
on
its
provided
mask
the
standard
over
it
stacks
the
only
counter.
program
Request(I§Q)
*
Interrupt
A
Low
level
input
the
mask
provided
machine
it
state
also
has
lower
a
*
E,
Q
is
similar
E
to
clock
which
signal
the
leading
edge
*MRDY
This
input
control
time.
access
*
DMA/BREQ
The
DMA/BREQ input
acquiring
the
MPU
dynamic
refresh.
memory
taken
off
the
bus.
~HD45821E
(PIA
3
Interface
Peripheral
(U
pin
arrangement
(GNDHM
PM
PM
PM
PM
PM
,As
PM
PA1
HD46821P
no
(Pm)
Pm
N215
P91
PB*
:Es
6
C82
(5\/WEE: : RM
(NMI)
this
input
requests
on
Anon-maskeble
and
also
has
higher
a
this
input
will
pin
bit(F)
in
the
CC
Interrupt
Request(IRQ),and
of
the
contents
this
will
pin
on
in
bit(I)
the
CC
provides
slower
a
priority
than
FIRQ.
theHD468OO
bus
timing
leads
E.Address
of
is
latched
Q.
Data
signal
allows
stretching
_
fa
provides
method
another
bus
for
use.
When
BA
goes
Adapter)
CA'
CM
WOT
%§
R50
RS,
m
0
32
D1
nz
DJ
FED#
05
D6
Z
Q
CSD
T2
nonmaskable
that
a
interrupt
cannot
priority
than
E I R Q , I R Q
initiate
fast
interrupt
a
This
is_§lear.
sequence
is
fast
in
condition
code
register
initiate
interrupt
an
is
clear.
Since
IRQ
to
interrupt
response
signal
is
§Z52;Q
from
the
will
MPU
be
the
falling
on
of
and
E
of
suspending
execution
Typical
include
uses
the
device
Low,
DMA
*
PIA
INTERFACE
_
__.
._
,___
__
K
FLA
aleuirectional
The
bi-directional
(D6'D7)allow
data
between
The
data
bus
output
three
devices
state
in
the
high
impedance(off)
when
exception
PIA
read
operation.
a
*
PIA
Enable(E)
The
enable
pulse,E,
timing
signal
I
to
the
Timing
PIA.
signals
is
referenced
and
trailing
edges
*
PIA
Read/wri§;e
This
is
signal
MPU
to
control
interrupt
inhibited
be
software
o r
sequence
has
priority
the
that
sense
the
and
Request
sequence
stacks
the
entire
than
FIRQ,IRQ
quadrature
a
valid
with
of
edge
E.
extend
data
Q
to
and
DMA
and
should
be
SIGNALS
FOR
MPU
_
_
_
._
_
.
uataLD»~jU7)
Qines
data
the
transfer
of
the
and
the
MPU
PIA.
drivers
are
that
remain
state
the
MPU
performs
is
the
only
that
is
supplied
of
all
other
the
to
leading
of
the
E
pulse.
the
generated
by
the
direction
of
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