Holtek BS83B24C Manual page 52

SLOW Mode to FAST Mode Switching
In SLOW mode the system clock is derived from f
FAST mode from f
clock will respectively be switched to f
However, if f is not used in SLOW mode and thus switched off, it will take some time to re-
H
oscillate and stabilise when switching to the FAST mode from the SLOW Mode. This is monitored
using the HIRCF bit in the HIRCC register. The time duration required for the high speed system
oscillator stabilization is specified in the relevant characteristics.
Entering the SLEEP Mode
There is only one way for the device to enter the SLEEP Mode and that is to execute the "HALT"
instruction in the application program with both the FHIDEN and FSIDEN bits in the SCC register
equal to "0". In this mode all the clocks and functions will be switched off except the WDT function.
When this instruction is executed under the conditions described above, the following will occur:
• The system clock will be stopped and the application program will stop at the "HALT"
instruction.
• The Data Memory contents and registers will maintain their present condition.
• The I/O ports will maintain their present conditions.
• In the status register, the Power Down flag PDF will be set, and WDT timeout flag TO will be
cleared.
• The WDT will be cleared and resume counting as the WDT function is always enabled.
Rev. 1.00
, the CKS2~CKS0 bits should be set to "000" ~ "110" and then the system
SUB
~ f /64.
H H
�HIDEN=0� �SIDEN=0
HALT inst��ction is exec�ted
�HIDEN=0� �SIDEN=1
HALT inst��ction is exec�ted
IDLE0 Mode
�HIDEN=1� �SIDEN=1
HALT inst��ction is exec�ted
IDLE1 Mode
�HIDEN=1� �SIDEN=0
HALT inst��ction is exec�ted
IDLE2 Mode
5�
BS83B24C/BS83C40C
Touch Flash MCU
. When system clock is switched back to the
SUB
SLOW Mode
CKS�~CKS0 = 000~110
FAST Mode
SLEEP Mode
�e���a�� 0�� �01�