Rev. 1.60
74
August 20, 2019
Rev. 1.60
75
August 20, 2019
BS66F340/BS66F350/BS66F360/BS66F370
Touch A/D Flash MCU with LED Driver
BS66F340/BS66F350/BS66F360/BS66F370
Touch A/D Flash MCU with LED Driver
Bit 1
LXTF
: LXT oscillator stable flag
0: LXT unstable
1: LXT stable
This bit is used to indicate whether the LXT oscillator is stable or not. When the
LXTEN bit is set to 1 to enable the LXT oscillator, the LXTF bit will first be cleared
to 0 and then set to 1 after the LXT oscillator is stable.
Bit 0
LXTEN
: LXT oscillator enable control
0: Disable
1: Enable
Operating Mode Switching
These devices 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 a 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