Ublox NINA-B4 Series, Руководство по системной интеграции, Страница: 14 / 61

NINA-B4 series - System integration manual
UBX-19052230 - R09 Functional description Page 14 of 61
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Figure 5: NINA-B41 pin assignments
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For more information about the pin assignments, see also 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 (~1s).
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] .
The information in this section describes 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 also reference
[21] .
1.9.1 External crystal
NINA-B4 modules have two input pins for connecting an external low-frequency crystal (LFXO) as
source for the low power clock. This setup enables NINA-B4 modules to run with the lowest overall
power consumption.
Table 7 describes the details of the crystal used on EVK-NINA-B4.
Table 7: Components used on the NINA-B4 EVK evaluation kit
Component Value Note
Crystal 32.768 kHz – 20 ppm EPSON FC-12M used on NINA-B4 EVK