In applications which are peak current
limited, there are two options for reducing active current in RUN and SLEEP modes:
- If 32kHz provides sufficient performance, run MCLK from LFCLK. MCLK can be selected to run from LFCLK with SYSOSC disabled. If no fast handling of events is needed, SYSOSC asynchronous
requests can be disabled to ensure that the device always runs from LFCLK. This provides the lowest possible current with the CPU still running (RUN2). See the MCLK, SYSOSC, and Operating Mode Selection sections.
- If 32kHz does not provide sufficient performance, MCLK can be selected to
run from SYSOSC with SYSOSC set to low frequency (4MHz). With MCLK running
from SYSOSC, the MDIV divider for MCLK can be applied to reduce current
consumption. For example, MCLK can be configured to run as low as 250kHz by
setting MDIV to /16 when sourced from SYSOSC running at 4MHz. See the MCLK section.