Modem User Manual

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5.11.7 SIM Detection (SIMDET)
SIMDET is used to determine whether a SIM card has been inserted into or removed
from the SIM card holder. You should normally wire it to the ‘card inserted switch’ of
the SIM card holder, but different implementations are possible.
When left open, an internal pull-up resistor maintains the signal high and means ‘SIM
card missing’ to the wireless modem. When pulled low the radio device assumes a
SIM card is inserted. SIMDET is a Digital IO signal input with characteristics defined in
paragraph 5.3.1.
In order to meet regulatory approval requirements, the SIMDET
function must be implemented in the host application.
5.12 Service/Programming
Pin Name Direction Function
58 SERVICE Input Flash programming enable signal
The SERVICE interface is flash programming enable input. The SERVICE pin is driven
active high by the host application using either a logic control input or applying a dc
voltage (common in legacy applications) to begin a flash download. This pin should
be pulled low or grounded during normal use.
The SERVICE signal drives an N-channel FET switch which has a resistive divider on
the input.
Figure 5.12-1 SERVICE Pin Interface
NOTE