Sony Ericsson GS64 - Manual (Page 44)

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5.8.2 Module On & Off Sequence
Figure 5.8-1 shows typical powering-on and powering-off sequences, using the two
optional hardware interfaces.
Figure 5.8-1 Typical Power-On & Power-Off Sequences
Event Description
A VCC is applied to the module, PON_L is pulled high internally
B PON_L is pulled low by the user application, initiating a power-on sequence
C VREF presence indicates a successful power-on initialization
D PON_L is pulled low by the user application, initiating a power-off sequence
E VREF absence indicates network de-registration and shut-down complete
F VCC can be safely removed
G VCC is applied to the module, PON_H is pulled low internally
H PON_H is pulled high & retained high, initiating a power-on sequence
I VREF presence indicates a successful power-on initialization
J PON_H is released, initiating a power-off sequence
K VREF absence indicates network de-registration and shut-down complete
L VCC can be safely removed