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.

NOTE

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

LZT 123 1834

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