QSG
‐
8475,
Rev.
New
HOLT
INTEGRATED
CIRCUITS
11/7/13
4
Jumper
Functions
REF
NAME
DEFAULT
DESCRIPTION
J1
LED_GND_LINK
ON
Link
for
BIT
LED
current
to
ground
J2
‐
ON
Supplies
3.3V
to
the
1MHz
crystal
oscillator
J3
EXTCLK
ON
To
use
external
clock,
disconnect
link
and
apply
a
VLOGIC
level
clock
to
the
CLK
test
point
J4
LINK
ON
Link
for
supply
indicator
LED
J5
VLOGIC_LINK
ON
Link
for
device
VDD
supply
current
(this
supplies
the
HI
‐
8475
only)
and
can
be
used
to
measure
device
current,
make
sure
LED
link
is
OFF
Test
Point
and
Connector
Functions
REF
NAME
DESCRIPTION
TP1
CLK
Use
for
external
clock
connection,
disconnect
link
J3
and
apply
a
VLOGIC
level
clock
CLK
TP2/TP5
GND
Ground
Test
Point
TP3/4
VSUPPLY/VLOGIC
Connect
3.3
or
5V
supply
TP6
UPDATE
Test
point
for
Update
signal
indicates
when
ARINC
word
has
been
received
J7
pins
1
‐
32
Received
Data
ARINC
data
bits
1
‐
32
respectively
J7
pin
35
CLK
1
MHz
Clock
J7
pin
38
VLOGIC
VLOGIC
Supply
J7
pin
39,40
GND
Board
Ground
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