C8051F980-C-GM Datasheet, PDF (196/325 Pages) Silicon Laboratories – Ultra Low Power, 8-2 kB Flash, Capacitive Sensing MCU

C8051F99x-C8051F98x
SFR Definition 19.4. OSCXCN: External Oscillator Control
Bit
7
Name XCLKVLD
Type
R
Reset
0
6
5
4
XOSCMD[2:0]
R/W
R/W
R/W
0
0
0
3
Reserved
R/W
0
2
1
0
XFCN[2:0]
R/W
R/W
R/W
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 Bits.
Configures the external oscillator circuit to the selected mode.
00x: External Oscillator circuit disabled.
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 Read = 0b. Must Write 0b.
2:0 XFCN External Oscillator Frequency Control Bits.
Controls the external oscillator bias current.
000-111: See Table 19.1 on page 190 (Crystal Mode) or Table 19.2 on page 191 (RC
or C Mode) for recommended settings.
196
Rev. 1.2