Ubx-13004618 - R28 - Ublox TOBY-L2 Series System Integration Manual
Lte/dc-hspa+/egprs modules
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Also See for TOBY-L2 Series:
- System integration manual (141 pages) ,
- User manual (31 pages) ,
- System integration manual (158 pages)
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Figure 14
shows the module power-on sequence from the not-powered mode, with following phases:
The external supply is applied to VCC or 3.3Vaux supply inputs, representing the start-up event.
PWR_ON and RESET_N or PERST# pins suddenly rise to high logic level due to internal pull-ups.
V_BCKP RTC supply output is suddenly enabled by the module as VCC reaches a valid value.
All the generic digital pins 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.
Start-up
event
VCC or 3.3Vaux
V_BCKP
PWR_ON
RESET_N or PERST#
V_INT
Internal Reset
System State
Tristate / Floating Internal Reset
BB Pads State
0 ms
Figure 14: TOBY-L2 and MPCI-L2 series power-on sequence description
The greeting text can be activated by means of +CSGT AT command (see u-blox AT Commands
Manual [3]) to notify the external application that the module is ready to operate (i.e. ready to reply to
AT commands) and the first AT command can be sent to the module, given that autobauding has to
be disabled on the UART to let the module sending the greeting text: the UART has to be configured
at fixed baud rate (the baud rate of the application processor) instead of the default autobauding,
otherwise the module does not know the baud rate to be used for sending the greeting text (or any
other URC) at the end of the internal boot sequence.
☞
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.
o
The USB interface to sense the start of the MPCI-L2 module power-on sequence: the module,
o
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 USB Revision 2.0 specification [7].
☞
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 / MPCI-L2 module is fully ready to operate, the host application processor
should not send any AT command over AT communication interfaces (USB, UART) of the module.
☞
The duration of the TOBY-L2 and MPCI-L2 series modules' switch-on routine can vary depending
on the application / network settings and the concurrent module activities.
UBX-13004618 - R28
TOBY-L2 and MPCI-L2 series - System Integration Manual
Start of interface
configuration
OFF
Internal Reset → Operational
~5 ms
~10 ms
System description
Module interfaces
are configured
ON
Operational
~20 s
Page 31 of 164
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