NINA-B4 series - System integration manual
UBX-19052230 - R06
Functional description
Page 13 of 45
C1-Public
1.8.2
NINA-B41 pins
The u-connectXpress software running on NINA-B41 modules has fixed pin multiplexing that
implements a given set of features like the UART connection. The pin assignments for NINA-B41 are
shown in Figure 5.
Figure 5: NINA-B41 pin assignments
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For more detailed information about pin assignment, see the NINA-B41 series data sheet [3].
1.9
Low power clock
NINA-B4 modules use a 32.768 kHz low power clock to enable different sleep modes.
The clock can be generated from either of the following sources:
•
Internal oscillator
•
External crystal (LFXO)
•
External clock source such as a crystal oscillator (TCXO)
The u-connectXpress software automatically senses the clock input and uses the source from the
external crystal – if one is available. Otherwise, the software uses the source from the internal
oscillator. This automatic sense functionality adds some additional time delay during startup (about
1s). If the startup time is critical or more detailed settings are needed, set the low power clock settings
using AT commands. See also section 1.10.
To reach the lowest sleep current consumption of the NINA-B4 module, an external crystal or external
clock source shall be used. The internal oscillator gives higher sleep current but of course a leaner
BOM. For more information about sleep and other power modes, see the respective data sheet [2] [3].
Sections 1.10.1 to 1.10.3 describe the different hardware options for the low power clock source and
explain the implications the clock choices have on both the cost and performance of NINA-B4
modules. For practical guidance on how to configure the oscillator on nRF5 open CPU modules, see
reference [21].
