Linx Technologies RXM-GPS-F4 - Manual (Page 8)

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Module Power-up Sequence
The module requires a specific sequence to power up and begin normal
operation. When power is first applied the module enters a “ready-to-start”
state while the Real Time Clock (RTC) starts up and settles. It awaits a
pulse on the ON_OFF line to enter Full Power Mode.
The RTC start time is variable, so the host needs to either monitor the
RFPWRUP line for a high pulse or wait for at least one second before
pulsing the ON_OFF line. An example flowchart is shown in Figure 8.
Module Power-down Sequence
The module requires a controlled power-down sequence. Uncontrolled
removal of power while the module is operating carries the risk of data
corruption. The consequences of this corruption range from longer TTFF
to complete system failure. The appropriate procedure to remove power is
shown in Figure 9.
Start
Power on the
module
Wait for ≥1 second
Pull ON_OFF high
for ≥100ms
The module is in
Full Power Mode
1
second timer
expired?
End
Data output
from the
module?
Yes
No
Yes
No
Start
Send System turn
off message to the
module (117)
Wait for ≥1 second
for the module to
enter Hibernate
Mode
Pull ON_OFF high
for ≥100ms when
the module is in
Full Power Mode
Remove power
from the module
End
Figure 8: F4 Series GPS Receiver Power Power-up Sequence
Figure 9: F4 Series GPS Receiver Power Power-down Sequence