SYSTEM CONNECTOR INTERFACE
45
LZT 123 8020 R1A
38
OUT1
DCD
Programmable Output 1/DCD
Data Carrier Detect
40 OUT4 CTS Programmable Input/Output 4/CTS
Signals which have an entry in the Default Signal column in the
above table are multiplexed.
The operational modes of multiplexed signals are controlled by
AT commands and also by intrinsic functions available to an
embedded application.
The following table gives you the input impedance. These
values only apply when the ports are configured as input
signals.
Parameter Min.
Typ.
Max.
Units
Input impedance (pull-up)
50
100
120
k
Ω
Note!
I/O6 (LED) doesn’t have an internal pull up. If this pin is
configured as an input, it should not be left floating.
I/O7 (TD3) has a pull down instead of a pull up.
5.15 Extended I/O capabilities
To increase flexibility and variety of radio device peripherals,
the RS232 hardware flow control shares its physical interface
with the extended general purpose I/O capability. This sharing
means that it is not feasible to operate all these features
concurrently, however, with care, dynamic switching from one
feature to another is possible.
5.15.1
LED/IO6 Capabilities
The LED function pin can be used as a general purpose digital
I/O when the flashing LED function is not required. However,
this pin does not have an on-board pull-up resistor. It is required
that an external pull-up or pull-down resistor be provided by the
host circuitry when either not used or when used as a digital
input.
5.15.2
I#/O#
If pins labelled I# and O# are not being used for an alternative
function they may be used for general purpose inputs or outputs
respectively. The inputs have an on-board 100k pull-up resistor
and the outputs are driven rail-to-rail at 2.75V levels.
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