C8051T630 Datasheet, PDF (107/221 Pages) Silicon Laboratories – Mixed-Signal Byte-Programmable EPROM MCU

C8051T630/1/2/3/4/5
SFR Definition 19.5. OSCXCN: External Oscillator Control
Bit
7
6
5
4
3
2
1
0
Name
XOSCMD[2:0]
XFCN[2:0]
Type
R
R/W
R
R/W
Reset
0
0
0
0
0
0
0
0
SFR Address = 0xB1
Bit
Name
Function
7
Unused Read = 0; Write = Don’t Care
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 with divide by 2 stage.
101: Capacitor Oscillator Mode with divide by 2 stage.
11x: Reserved.
3
Unused Read = 0; Write = Don’t Care
2:0 XFCN[2:0] _{External Oscillator Frequency Control Bits.}
Set according to the desired frequency range for RC mode.
Set according to the desired K Factor for C mode.
XFCN
000
001
010
011
100
101
110
111
RC Mode
f 25 kHz
25 kHz f 50 kHz
50 kHz f 100 kHz
100 kHz f 200 kHz
200 kHz f 400 kHz
400 kHz f 800 kHz
800 kHz f 1.6 MHz
1.6 MHz f 3.2 MHz
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
Rev. 1.0
107