Rev. 1.10
42
November 04, 2019
Rev. 1.10
43
November 04, 2019
HT45F5Q-3
Battery Charger Flash MCU
HT45F5Q-3
Battery Charger 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 if the WDT function is enabled. If the WDT
function is disabled, the WDT will be cleared and then stopped.