LENA-R8 series - System integration manual
UBX-22015376 - R02
System description
Page 16 of 116
C1-Public
GNSS
software standby mode
Software standby
mode allows control over the backup state with the command UBX-RXM-PMREQ.
VCC_GNSS
must be supplied, however V_CORE / V_RF supply is internally disabled. The internal V_IO
supply maintains the BBR, RTC, and PIOs.
Entering the software standby
mode clears the RAM memory including the receiver configuration. To
maintain the configuration, store it on both RAM and battery-backed RAM (BBR)
layers. Configuration
in OTP memory is always maintained.
The software standby
mode can be set for a specific duration, or until the receiver is woken up by a
signal at a wake-
up source defined in UBX
-RXM-PMREQ. Possible wake-up source is the
EXTINT
pin.
See the u-blox M10 SPG 5.10 interface description
for more info on UBX-RXM-PMREQ message.
As the internal V_IO is supplied, the PIOs can be driven b
y an external host processor. No buffers are
required for isolating the PIOs, which reduces cost.
☞
The "force" flag must be set in UBX
-RXM-PMREQ to enter software standby mode.
☞
VBCKP_GNSS
should be left open if not used
☞
For further details about GNSS backup mode, see the UBX-M10050-KB integration manual
the u-blox M10 SPG 5.10 interface description
1.6
Cellular power management
1.6.1
Cellular supply input (VCC)
The cellular system of the LENA-R8 series modules must be supplied via the three
VCC
pins that
represent the cellular system power supply input.
The
VCC
pins are internally connected to the RF power amplifier and to the integrated Power
Management Unit: all supply voltages needed by the module are generated from the
VCC
supply by
integrated voltage regulators, including the
V_INT
supply for generic digital interfaces (as the UARTs,
I2C, I2S, GPIOs) and the
VSIM
supply for the SIM interface.
During operation, the current drawn by the LENA-R8 series modules through the
VCC
pins can vary
by several orders of magnitude. This ranges from the pulse of current consumption during GSM
transmitting bursts at maximum power level in connected mode (as described in section
) to
the low current consumption during the low power idle mode (as described in section
LENA-R8 series modules provide separate supply inputs over the three
VCC
pins:
•
VCC
pins #52 and #53 represent the supply input for the internal RF power amplifier, demanding
most of the total current drawn when RF transmission is enabled during a voice/data call
•
VCC
pin #51 represents the supply input for the internal baseband Power Management Unit and
the internal transceiver, demanding minor part of the total current drawn
provides a simplified block diagram of LENA-R8 series modules internal VCC supply routing.
53
VCC
52
VCC
51
VCC
LENA-R8 series
Power
Management
Unit
Memory
Baseband
Processor
Transceiver
LTE / 3G / 2G
Power Amplifiers
Figure 4: LENA-R8 series modules internal VCC supply routing simplified block diagram
