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ST9 USER GUIDE
Figure 25. INTCLK and CPUCLK Flow Chart
Yes
No
WFI
Instruction
No
Yes
CKAF_SEL==0
No
Yes
No
Yes
LPOWFI==0
CK_AF
Present
No
CSU_CKSEL=0
No
Yes
XT_DIV16==0
Yes
WFI_CKSEL==0
No
No
Yes
CSU_CKSEL==0
Yes
CK_AF
Present
No
Yes
Yes
DX2:0==7
CKAF_SEL=0
CKAF_ST=0
CKAF_SEL=1
CKAF_ST=1
No
DX2:0==7
CSU_CKSEL=0
CSU_CKSEL=0
INTCLK=
CLOCK2/16
CK_AF
CLOCK2/16 Previous CK_AF
CLOCK
PLL-CLOCK
CLOCK2 CLOCK2
(PLL OFF) (PLL ON)
CLOCK2/16
(PLL OFF)
Fast mode
LOW POWER
PLL is OFF
CPUCLK Stopped
62/146
Reduced power consumption
Slow mode
Reduced power consumption
CPUCLK=INTCLK/N