Data Sheet

October 2017 BNO080 Datasheet 1000-3927
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Figure 1-7: 32.768kHz crystal connection
Clock source selection is done during startup using the CLKSEL0 and CLKSEL1 pins. Figure 1-8 shows how to
select each source.
Source
CLKSEL0
CLKSEL1
Crystal
0 or unconnected
Connected to crystal
External
1
1
Internal
1
0 or unconnected
Figure 1-8: Clock Source Selection
CLKSEL0 is configured with an internal pulldown at startup. After CLKSEL0 has been sampled, if it is found to be
a 1, the internal pulldown is disabled to avoid unnecessary power consumption. If either the external or internal
clock sources are selected then CLKSEL1 is configured as an input with a pulldown. CLSKSEL1 is then sample
and the clock source determined. After CLKSEL1 has been sampled, if it is found to be a 1, the internal pulldown
is disabled to avoid unnecessary power consumption.
Figure 1-9: External clock connection