C8051F336/7/8/9
SFR Definition 19.5. OSCXCN: External Oscillator Control
Bit
7
6
5
4
3
2
1
XFCN[2:0]
R/W
0
Name XTLVLD
XOSCMD[2:0]
Type
R
0
R/W
0
R
0
Reset
0
0
0
0
0
SFR Address = 0xB1;
Bit
Name
Function
7
XTLVLD
Crystal Oscillator Valid Flag.
(Read only when XOSCMD = 11x.)
0: Crystal Oscillator is unused or not yet stable.
1: Crystal Oscillator is running and stable.
6:4 XOSCMD[2:0] External Oscillator Mode Select.
00x: External Oscillator circuit off.
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
UNUSED
Read = 0; Write = Don’t Care
2:0
XFCN[2:0]
External Oscillator Frequency Control Bits.
Set according to the desired frequency for Crystal or RC mode.
Set according to the desired K Factor for C mode.
XFCN
000
001
010
011
100
101
110
111
Crystal Mode
f ≤ 32 kHz
32 kHz < f ≤ 84 kHz
84 kHz < f ≤ 225 kHz
225 kHz < f ≤ 590 kHz 100 kHz < f ≤ 200 kHz
590 kHz < f ≤ 1.5 MHz 200 kHz < f ≤ 400 kHz
1.5 MHz < f ≤ 4 MHz
4 MHz < f ≤ 10 MHz
RC Mode
f ≤ 25 kHz
25 kHz < f ≤ 50 kHz
50 kHz < f ≤ 100 kHz
C Mode
K Factor = 0.87
K Factor = 2.6
K Factor = 7.7
K Factor = 22
K Factor = 65
K Factor = 180
K Factor = 664
K Factor = 1590
400 kHz < f ≤ 800 kHz
800 kHz < f ≤ 1.6 MHz
10 MHz < f ≤ 30 MHz 1.6 MHz < f ≤ 3.2 MHz
122
Rev. 0.2
SILICON [ SILICON ]
