Ope�Ating Mode Switching - Holtek BS83B24C Manual

Operating Mode Switching
The device can switch between operating modes dynamically allowing the user to select the best
performance/power ratio for the present task in hand. In this way microcontroller operations that
do not require high performance can be executed using slower clocks thus requiring less operating
current and prolonging battery life in portable applications.
In simple terms, Mode Switching between the FAST Mode and SLOW Mode is executed using the
CKS2~CKS0 bits in the SCC register while Mode Switching from the FAST/SLOW Modes to the
SLEEP/IDLE Modes is executed via the HALT instruction. When an HALT instruction is executed,
whether the device enters the IDLE Mode or the SLEEP Mode is determined by the condition of the
FHIDEN and FSIDEN bits in the SCC register.
SLEEP
HALT inst��ction exec�ted
CPU stop
�HIDEN=0
�SIDEN=0
f off
H
f off
SUB
Rev. 1.00
FAST
f =f ~f /64
SYS H H
f on
H
CPU ��n
f on
SYS
f on
SUB
IDLE2
HALT inst��ction exec�ted
CPU stop
�HIDEN=1
�SIDEN=0
f on
H
f off
SUB
50
BS83B24C/BS83C40C
Touch Flash MCU
SLOW
f =f
SYS SUB
f on
SUB
CPU ��n
f on
SYS
f on/off
H
IDLE0
HALT inst��ction exec�ted
CPU stop
�HIDEN=0
�SIDEN=1
f
f
SUB
IDLE1
HALT inst��ction exec�ted
CPU stop
�HIDEN=1
�SIDEN=1
f on
H
f on
SUB
�e���a�� 0�� �01�
off
H
on