MTX
‐
3G
‐
JAVA
Family
www.mtx
‐
terminals.com
www.mtxm2m.com
2015/10
v1.6
Page
56
/
109
MTX
M2M®
by
MATRIX
ELECTRONICA
S.L.U
4.4.3
I2C
bus
I2C
is
a
serial,
8
‐
bit
oriented
data
transfer
bus
for
bit
rates
up
to
400kbps
in
Fast
mode.
It
consists
of
two
lines,
the
serial
data
line
I2CDAT
and
the
serial
clock
line
I2CCLK.
The
MTX
‐
3G
‐
JAVA
modem
acts
as
a
single
master
device,
e.g.
the
clock
I2CCLK
is
driven
by
the
modem.
I2CDAT
is
a
bi
‐
directional
line.
Each
device
connected
to
the
bus
is
software
which
is
identified
by
a
unique
7
‐
bit
address.
Simple
master/slave
relationships
exist
at
all
times;
the
modem
operates
as
a
master
‐
transmitter
or
as
a
master
‐
receiver.
The
customer
application
transmits
or
receives
data
only
at
the
modem’s
request.
1.
2C
lines
are
Open
Drain.
Internal
10kOhm
pull
‐
up
resistors
are
mounted,
so
there
is
no
need
to
fit
them
to
the
host
application.
2.
According
to
the
I2C
Bus
Specification
Version
2.1,
a
maximum
rise
time
of300ns
is
permitted
for
the
fast
mode.
There
is
also
a
maximum
VOL=0.4V
at
3mA
specified.
3.
The
value
of
the
pull
‐
up
depends
on
the
capacitive
load
of
the
whole
system
(I2C
Slave
+
lines).
The
maximum
sink
current
of
I2CDAT
and
I2CCLK
is
4mA.
4.
If
lines
are
unused,
keep
pins
open
Use
the
AT^SSPI
command
or
Java
class
to
configure
and
activate
the
I2C
bus.
The
picture
below
shows
the
I2C
interface
is
powered
from
an
internal
VEXT
supply
line
so
the
I2C
interface
will
be
properly
shut
down
when
the
modem
enters
the
Power
‐
down
mode.
Signal
Direction
Description
I2CCLK
Output
I2C
bus
clock
signal
1234
I2CDAT
I/O
I2C
data
bus
1234
GND
‐
Ground
connection
