Holtek HT66F20 Manual page 64

SLOW Mode to NORMAL Mode Switching
In SLOW Mode the system uses either the LXT or LIRC low speed system oscillator. To switch
back to the NORMAL Mode, where the high speed system oscillator is used, the HLCLK bit should
be set to "1" or HLCLK bit is "0", but CKS2~CKS0 is set to "010", "011", "100", "101", "110", or
"111". As a certain amount of time will be required for the high frequency clock to stabilise, the
status of the HTO bit is checked. The amount of time required for high speed system oscillator
stabilization depends upon which high speed system oscillator type is used.
I D L E N = 1 , F S Y S O N = 1
H A L T i n s t r u c t i o n i s e x e c u t e d
Rev. 2.50
HT66F20/HT66F30/HT66F40/HT66F50/HT66F60
HT66FU30/HT66FU40/HT66FU50/HT66FU60
A/D Flash MCU with EEPROM
C K S 2 ~ C K S 0 ¹ 0 0 0 B , 0 0 1 B a s H L C L K = 0
o r H L C L K = 1
W D T a n d L V D a r e a l l o f f
I D L E N = 0
H A L T i n s t r u c t i o n i s e x e c u t e d
S L E E P 0 M o d e
W D T o r L V D i s o n
I D L E N = 0
H A L T i n s t r u c t i o n i s e x e c u t e d
S L E E P 1 M o d e
I D L E N = 1 , F S Y S O N = 0
H A L T i n s t r u c t i o n i s e x e c u t e d
I D L E 0 M o d e
I D L E 1 M o d e
64
S L O W M o d e
N O R M A L M o d e
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