ML51/ML54/ML56
Sep. 01, 2020
Page
141
of 719
Rev 2.00
ML
51
/ML
54
/ML
5
6 S
E
RI
E
S
TECHNI
CA
L
RE
F
E
R
E
NC
E
M
A
NU
A
L
ML51/M
L54
/M
L56
Series
Tec
hnical Reference
Manual
CKSWT
– Clock Switch (TA Protected)
Register
SFR Address
Reset Value
CKSWT
96H, PAGE 0, TA protected
0011 _0000 b
7
6
5
4
3
2
1
0
HXTST
LXTST
HIRCST
LIRCST
ECLKST
OSC[2:0]
R
R
R
R
R
W
Bit
Name
Description
[7]
HXTST
High Speed External Crystal/Resonator 4 MHz to 24 MHz Status
0 = High speed external crystal/resonator is not stable or is disabled.
1 = High speed external crystal/resonator is enabled and stable.
[6]
LXTST
Low Speed External Crystal/Resonator 32.768 kHz Status
0 = Low speed external crystal/resonator is not stable or is disabled.
1 = Low speed external crystal/resonator is enabled and stable.
[5]
HIRCST
High-Speed Internal Oscillator 24 MHz Status
0 = High-speed internal oscillator is not stable or disabled.
1 = High-speed internal oscillator is enabled and stable.
[4]
LIRCST
Low Speed Internal Oscillator 38.4 kHz Status
0 = Low speed internal oscillator is not stable or is disabled.
1 = Low speed internal oscillator is enabled and stable.
[3]
ECLKST
External Clock Input Status
0 = External clock input is not stable or disabled.
1 = External clock input is enabled and stable.
[2:0]
OSC[2:0]
Oscillator Selection Bits
This field selects the system clock source.
00x = Internal 24 MHz oscillator. Defaul value accoding to HIRCEN(CKEN.5) enabled.
01x = External oscillator clock source accoding to ECLKEN(CKEN.3) enabled.
10x = Internal 38.4 kHz oscillator according to LIRCEN(CKEN.4) enabled.
110 = External High speed crystal/resonator clock source (4 MHz ~ 24 MHz) accoding to
EHXTEN(CKEN.7) enabled.
111 = External Low speed crystal/resonator clock source (32.768 kHz) accoding to
ELXTEN(CKEN.6) enabled.
Note that this field is write only. The read back value of this field may not correspond to the
present system clock source.
