8.4.4 XOSC0CN: External Oscillator Control
Bit
7
6
5
4
3
2
1
0
Name
XCLKVLD
XOSCMD
Reserved
XFCN
Access
R
RW
RW
RW
Reset
0
0x0
0
0x0
SFR Page = 0x0; SFR Address: 0xB1
Bit
Name
Reset
Access
Description
7
XCLKVLD
0
R
External Oscillator Valid Flag.
Provides External Oscillator status and is valid at all times for all modes of operation except External CMOS Clock Mode
and External CMOS Clock Mode with divide by 2. In these modes, XCLKVLD always returns 0.
Value
Name
Description
0
NOT_SET
External Oscillator is unused or not yet stable.
1
SET
External Oscillator is running and stable.
6:4
XOSCMD
0x0
RW
External Oscillator Mode.
Value
Name
Description
0x0
DISABLED
External Oscillator circuit disabled.
0x2
CMOS
External CMOS Clock Mode.
0x3
CMOS_DIV_2
External CMOS Clock Mode with divide by 2 stage.
0x4
RC
RC Oscillator Mode.
0x5
C
Capacitor Oscillator Mode.
0x6
CRYSTAL
Crystal Oscillator Mode.
0x7
CRYSTAL_DIV_2
Crystal Oscillator Mode with divide by 2 stage.
3
Reserved
Must write reset value.
2:0
XFCN
0x0
RW
External Oscillator Frequency Control.
Controls the external oscillator bias current. The value selected for this field depends on the frequency range of the external
oscillator.
EFM8SB2 Reference Manual
Clocking and Oscillators
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