Rev. 1.00
50
September 11, 2018
Rev. 1.00
51
September 11, 2018
HT45F4050
A/D NFC Flash MCU
HT45F4050
A/D NFC Flash MCU
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 NORMAL Mode and SLOW Mode is executed using
the CKS2~CKS0 bits in the SCC register while Mode Switching from the NORMAL/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.
NORMAL
f
SYS
=f
H
~f
H
/64
f
H
on
CPU run
f
SYS
on
f
SUB
on
SLOW
f
SYS
=f
SUB
f
SUB
on
CPU run
f
SYS
on
f
H
on/off
IDLE0
HALT instruction executed
CPU stop
FHIDEN=0
FSIDEN=1
f
H
off
f
SUB
on
IDLE1
HALT instruction executed
CPU stop
FHIDEN=1
FSIDEN=1
f
H
on
f
SUB
on
IDLE2
HALT instruction executed
CPU stop
FHIDEN=1
FSIDEN=0
f
H
on
f
SUB
off
SLEEP
HALT instruction executed
CPU stop
FHIDEN=0
FSIDEN=0
f
H
off
f
SUB
off