CDMA and GSM / UMTS Mini Card Hardware Integration Guide
68
Proprietary and Confidential
2130114
In the event of a discrepancy in values between this guide and the Product Specification Document (PSD), the PSD takes precedence.
necessary
could
decrease
signal
rise
time,
increase
load
impedance,
and
cause
USIM
certification
failure.
•
Putting
an
optional
decoupling
capacitor
at
XIM_VCC
near
the
USIM
socket
is
recommended—the
longer
the
trace
length
(impedance)
from
the
socket
to
the
module,
the
greater
the
capacitance
requirement
to
meet
compliance
tests.
•
Putting
an
optional
series
capacitor
and
resistor
termination
(to
ground)
at
XIM_CLK
at
the
USIM
socket
to
reduce
EMI
and
increase
signal
integrity
is
recommended
if
the
trace
length
between
the
USIM
socket
and
module
is
long—47
pF
and
50
Ω
resistor
are
recommended.
•
Protect
the
USIM
socket
to
make
sure
that
the
USIM
cannot
be
removed
while
the
module
/
host
device
is
powered
up.
For
example,
you
could
place
the
socket
under
the
battery
(for
portable
devices);
consider
similar
options
for
other
device
types.
•
Test
your
first
prototype
host
hardware
with
a
Comprion
IT
3
USIM
test
device
at
a
suitable
testing
facility.
Extended AT commands
Several
proprietary
AT
commands
are
available
for
the
MC57xx
and
MC87xx
to
use
in
hardware
integration
design
and
testing
(these
commands
are
NOT
intended
for
use
by
end
users).
Refer
to
CDMA
Extended
AT
Command
Reference
(Document
2130621)
for
the
MC57xx,
or
MC87xx
Modem
Extended
AT
Command
Reference
(Document
2130616)
for
the
MC87xx
for
a
list
of
all
available
commands
and
descriptions
of
their
functionality.
Some
useful
commands
for
use
in
hardware
integration
are
listed
in
(MC57xx)
and
(MC87xx).
Table 5-4: MC57xx Extended AT commands
Command
Description
Internal commands
!OEM
Unlocks OEM protected commands
Modem state commands
!DIAG
Sets diagnostic mode
!BOOTHOLD
Resets modem and waits in boot loader
RF AT commands
!CHAN
Sets RF band and channel