Siemens MC45 User Manual

MC45 Hardware Interface Description
P R E L I M I N A R Y
MC45_HD_01_V00.02a Page 41 of 90 12.08.2002
3.3.3.2 Emergency shutdown using /EMERGOFF pin
Caution: Use the /EMERGOFF pin only when, due to serious problems, the software is
not responding for more than 5 seconds. Pulling the /EMERGOFF pin causes
the loss of all information stored in the volatile memory since power is cut off
immediately. Therefore, this procedure is intended only for use in case of
emergency, e.g. if MC45 fails to shut down properly.
The /EMERGOFF signal is available on the board-to-board connector. To control the
/EMERGOFF line it is recommended to use an open drain / collector driver. To turn the GSM
engine off, the /EMERGOFF line has to be driven to ground for ³ 3.2s.
Figure 11: Deactivating GSM engine by /EMERGOFF signal
BATT+
Internal reset
/EMERG-
OFF
generated by external application
max. 3.2s
generated by GSM engine
/IGT
VDD
How does it work:
· Voltage V
batt+
is permanentl
y
applied to the module.
· The module is active while the
internal reset signal is kept at
high level.
During operation of MC45 the
baseband controller generates
watchdog pulses at regula
r
intervals.
Once the EMERGOFF pin is
grounded these watchdog
pulses are cut off from the
power supply ASIC. The powe
r
supply ASIC shuts down the
internal supply voltages of MC45
after max. 3.2s and the module
turns off. Consequently, the
output voltage at VDD is
switched off.

Siemens MC45 Specifications

General

Brand	Siemens
Model	MC45
Category	Engine
Language	English