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8022
PIN
DESCRIPTION
Designation
Pin
#
Function
Designation
Pin
#
Function
v
S s
v C c
PROG
P00-P07
PortO
V
T
H
9
P10-P17
25-32
Port
1
P20-P27
33-36
Port 2
38-39
1-2
TO
T1
20
Circuit
GND
potential.
40
+
5V
circuit
power
supply.
37
Output strobe
for Intel®
8243
I/O expander.
10-17
8-bit
open-drain
port with
com-
parator
inputs.
The
switching
threshold
is
set externally
by
Vjh- Optional
pull-up
resistors
may
be added
via
ROM
mask
selection.
Port
threshold reference
pin.
25-32
8-bit
quasi-bidirectional
port.
8-bit
quasi-bidirectional
port.
P20-23
also
serve as a
4-bit
I/O
expander
for Intel®
8243.
8
Interrupt input
and
input pin
testable using the conditional
transfer instructions
JTO and
JNTO.
Initiates
an
interrupt
fol-
lowing a low
level input
if
inter-
rupt
is
enabled.
Interrupt
is
disabled
after
a
reset.
19
Input pin
testable using the
JT1
and JNT1
conditional transfer
instructions.
Can
be
designat-
ed
the timer/event counter
in-
put using the
STRT CNT
instruction.
Also serves as
the
zero-cross detection
input to
allow
zero-crossover sensing
of
slowly
moving
AC
inputs.
Op-
tional pull-up
resistor
may
be
added
via
ROM
mask
selection.
RESET
24
AV
S s
7
AVcc
3
SUBST
21
Varef
ANO,
AN1
6,5
ALE
18
XTAL
1
22
XTAL
2
23
Input
used
to
initialize
the proc-
essor by
clearing status
flip-
flops
and
setting
the
program
counter
to zero.
A/D
converter
GND
Potential.
Also establishes the lower
limit
of
the conversion range.
A/D
+
5V power
supply.
Substrate
pin
used
with a by-
pass
capacitor
to stabilize
the
substrate voltage
and improve
A/D
accuracy.
A/D
converter reference
volt-
age. Establishes the
upper
limit
of
the conversion range.
Analog
inputs to
A/D
converter.
Software
selectable on-chip
via
SEL ANO
and
SEL AN1
instructions.
Address
Latch Enable.
Signal
occurring
once
every
30
input
clocks (once every
cycle),
used as
an
output clock.
One
side
of crystal,
or inductor
input for internal
oscillator.
Also
input for
external
frequency
source. (Not
TTL
compatible.)
Other
side
of
timing control
ele-
ment. This
pin
is
not
connected
when
an external frequency
source
is
used.
THE STAND ALONE
8022
1
-xrv,
—
ih
VaREF
AVcc
Jn
[INPUT
I
AND
OUTPUTj
[INPUT
I
AND
OUTPUTj
[INPUT
I
AND
I
OUTPUTJ
6-37
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