C8051F970-A-GM Datasheet, PDF (252/454 Pages) Silicon Laboratories – Low Power Capacitive Sensing MCU with up to 32 kB of Flash

24.7. External Oscillator Registers
C8051F97x
Register 24.6. OSCXCN: External Oscillator Control
Bit
7
6
5
4
3
2
1
0
Name XCLKVLD
XOSCMD
Reserved
XFCN
Type
R
RW
RW
RW
Reset
0
0
0
0
0
0
0
0
SFR Page = 0x0; SFR Address: 0xB1
Bit
Name
Function
7
XCLKVLD 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.
0: External Oscillator is unused or not yet stable.
1: External Oscillator is running and stable.
6:4 XOSCMD External Oscillator Mode.
000: External Oscillator circuit disabled.
001: Reserved.
010: External CMOS Clock Mode.
011: External CMOS Clock Mode with divide by 2 stage.
100: RC Oscillator Mode.
101: Capacitor Oscillator Mode.
110: Crystal Oscillator Mode.
111: Crystal Oscillator Mode with divide by 2 stage.
3
Reserved Must write reset value.
2:0
XFCN 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.
Rev 1.0
253