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2014-07-02 - Tiny Gecko Family - d0034_Rev1.20
107
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Figure 11.6. HW-support for RC Oscillator Calibration
CMU_CALCTRL.REFSEL
AUXHFRCO
HFRCO
LFRCO
HFXO
LFXO
20- bit up- count er
CMU_CALCTRL.DOWNSEL
AUXHFRCO
HFRCO
LFRCO
HFXO
LFXO
TOP
Writ e t op- value using
CMU_CALCNT before
st art ing calibrat ion.
DOWNCLK Dom ain
UPCLK Dom ain
HFCLK Dom ain
= 0 ?
SYNC
(Default ) HFCLK
SYNC
20- bit up- count er
buffer
SYNC
20- bit down- count er
Set CMU_IF.CALRDY
CMU_CALCNT
DOWNCLK
UPCLK
Reload down- count er wit h
t op value in cont inouous
m ode.
Take snapshot of up- count er
in up- count er bufffer. If in
cont inouous m ode, rest art
up- count er from 0.
The counter operation for single and continuous mode are shown in Figure 11.7 (p. 107) and
Figure 11.8 (p. 107) respectively.
Figure 11.7. Single Calibration (CONT=0)
TOP
0
Calibrat ion St art ed
Calibrat ion St opped
(count ers st opped)
0
Down- count er
Up- count er
Up- count er sam pled and CALRDY
int errupt flag set .
Sam pled value available in
CMU_CALCNT.
Figure 11.8. Continuous Calibration (CONT=1)
TOP
0
Calibrat ion St art ed
0
Down- count er
Up- count er
Up- count er sam pled and CALRDY
int errupt flag set .
Sam pled value available in
CMU_CALCNT.
Up- count er sam pled and CALRDY
int errupt flag set .
Sam pled value available in
CMU_CALCNT.
Summary of Contents for EFM32TG
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