Module power-up sequence, Module power-down sequence – Linx Technologies RXM-GPS-F4 User Manual

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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

second timer

expired?

End

Data output

from the

module?

Yes

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