Ublox MPCI-L2 series, System Integration Manual

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TOBY-L2 and MPCI-L2 series - System Integration Manual
UBX-13004618 - R07 Advance Information System description
Page 31 of 158
Figure 14 shows the module power-on sequence from the not-powered mode, describing the following phases:

The external supply is applied to the
VCC
or
3.3Vaux
module supply inputs, representing the start-up event.

The PWR_ON and the RESET_N or PERST# pins suddenly rise to high logic level due to internal pull-ups.

The V_BCKP RTC supply output is suddenly enabled by the module as VCC reaches a valid voltage value.

All the generic digital pins of the module are tri-stated until the switch-on of their supply source ( V_INT ).

The internal reset signal is held low: the baseband core and all the digital pins are held in the reset state.
The reset state of all the digital pins is reported in the pin description table of
TOBY-L2 Series Data Sheet [1].

When the internal reset signal is released, any digital pin is set in a proper sequence from the reset state to
the default operational configured state. The duration of this pins’ configuration phase differs within generic
digital interfaces and the USB interface due to host / device enumeration timings (see section 1.9.1).

The module is fully ready to operate after all interfaces are configured.
VCC or 3.3Vaux
V_BCKP
PWR_ON
RESET_N or PERST#
V_INT
Internal Reset
System State
BB Pads State Internal Reset
→
Operational Operational
Tristate / Floating Internal Reset
OFF ON
0 ms ~10 ms ~20 s
Start of interface
configuration
Module interfaces
are configured
Start-up
event
~5 ms
Figure 14: TOBY-L2 and MPCI-L2 series power-on sequence description
The Internal Reset signal is not available on a module pin, but the host application can monitor:

The
V_INT
pin to sense the start of the TOBY-L2 module power-on sequence.

The USB interface to sense the start of the MPCI-L2 module power-on sequence: the module, as USB
device, informs the host of the attach event via a reply on its status change pipe for proper bus
enumeration process according to
Universal Serial Bus Revision 2.0 specification [6].
Before the switch-on of the generic digital interface supply source ( V_INT ) of the module, no voltage
driven by an external application should be applied to any generic digital interface of TOBY-L2 module.
Before the TOBY-L2 and MPCI-L2 series module is fully ready to operate, the host application processor
should not send any AT command over the AT communication interfaces (USB, UART) of the module.