
Rev. 1.10
42
March 02, 2020
Rev. 1.10
43
March 02, 2020
BS83A02L/BS83B04L
Ultra-Low Power Touch Key Flash MCU
BS83A02L/BS83B04L
Ultra-Low Power Touch Key Flash MCU
SLOW Mode to FAST Mode Switching
In SLOW mode the system clock is derived from f
SUB
. When system clock is switched back to the
FAST mode from f
SUB
, the CKS2~CKS0 bits should be set to “000”~“110” and then the system
clock will respectively be switched to f
H
~f
H
/64. However, if f
H
is not used in SLOW mode and thus
switched off, it will take some time to re-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 System Start
Up Time Characteristics.
FAST Mode
SLOW Mode
CKS2~CKS0=000~110
SLEEP Mode
FHIDEN=0, FSIDEN=0
HALT instruction is executed
IDLE0 Mode
FHIDEN=0, FSIDEN=1
HALT instruction is executed
IDLE1 Mode
FHIDEN=1, FSIDEN=1
HALT instruction is executed
IDLE2 Mode
FHIDEN=1, FSIDEN=0
HALT instruction is executed
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 the Watchdog time-out flag, TO,
will be cleared.
•
The WDT will be cleared and resume counting as the WDT function is always enabled.
Entering the IDLE0 Mode
There is only one way for the device to enter the IDLE0 Mode and that is to execute the “HALT”
instruction in the application program with the FHIDEN bit in the SCC register equal to “0” and the
FSIDEN bit in the SCC register equal to “1”. When this instruction is executed under the conditions
described above, the following will occur:
•
The f
H
clock will be stopped and the application program will stop at the “HALT” instruction, but