User's Manual

Reproduction forbidden without Fibocom Wireless Inc. written authorization - All Rights Reserved.
L850-GL Hardware User Manual Page
25
of
51
3.3 Control Signal
The L850 module provides two control signals for power on/off and reset operations, the pin defined as
shown in the following table:
Pin
Pin Name
I/O
Reset Value
Functions
Type
6
FUL_CARD_POWER_
OFF#
I
PU
Power on/off signal,internalpull-up
High or floating: Power on
Low : Power off
3.3/1.8V
67
RESET#
I
Reset signal, internal 10KΩ
pull-up,active low
1.8V
3.3.1 Module Start-Up
3.3.1.1 Start-upCircuit
The FUL_CARD_POWER_OFF# pin needs an external 3.3V or 1.8V pull up for booting up. The
VDD_1V8 should be provided from the external circuit. AP (Application Processor) controls the module
start-up，and the circuit design is shown in Figure3-4:
Figure 3-4 Circuit for Module Start-up Controlled by AP
3.3.1.2 Start-upTiming Sequence
After powering on, the module will start-up by pulling upthe FUL_CARD_POWER_OFF# signal for
more than 20ms (100msis recommended). Meanwhile, the module will output 1.8V voltage through
VSD2_1V8 pin and start the initialization process. The start-up timing is shown in Figure 3-5: