EFM32WG Datasheet, PDF (132/834 Pages) List of Unclassifed Manufacturers – The EFM32WG Wonder Gecko is the ideal choice for demanding 8-, 16-, and 32-bit energy sensitive applications.

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Figure 11.6. HW-support for RC Oscillator Calibration
DOWNCLK Dom ain
CMU_CALCTRL.DOWNSEL
AUXHFRCO
HFRCO
LFRCO
HFXO
DOWNCLK
LFXO
(Default ) HFCLK
20-bit down-counter
= 0?
UPCLK Dom ain
CMU_CALCTRL.REFSEL
AUXHFRCO
HFRCO
LFRCO
UPCLK
HFXO
LFXO
SYNC
20-bit up-counter
Reload down-count er wit h
top value in continouous
m ode.
TOP
Take snapshot of up-count er
in up-counter bufffer. If in
continouous m ode, restart
up-counter from 0.
20-bit up-counter
buffer
Write top-value using
CMU_CALCNT before
starting calibration.
HFCLK Dom ain
SYNC
CMU_CALCNT
SYNC
Set CMU_IF.CALRDY
The counter operation for single and continuous mode are shown in Figure 11.7 (p. 132) and
Figure 11.8 (p. 132) respectively.
Figure 11.7. Single Calibration (CONT=0)
Up-count er
0
TOP
Dow n -cou n t er
Up-count er sam pled and CALRDY
interrupt flag set.
Sam pled value available in
CMU_CALCNT.
0
Calibrat ion St art ed
Calibrat ion St opped
(counters stopped)
Figure 11.8. Continuous Calibration (CONT=1)
Up-count er
0
TOP
Dow n -cou n t er
Up-count er sam pled and CALRDY
interrupt flag set.
Sam pled value available in
CMU_CALCNT.
Up-count er sam pled and CALRDY
interrupt flag set.
Sam pled value available in
CMU_CALCNT.
0
Calibrat ion St art ed
2013-05-08 - Wonder Gecko Family - d0233_Rev0.50
132
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