C8051F38B-GMR View Datasheet(PDF) - Silicon Laboratories
Part Name
Description
Manufacturer
C8051F38B-GMR Datasheet PDF : 321 Pages
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C8051F380/1/2/3/4/5/6/7/C
SFR Definition 19.6. OSCXCN: External Oscillator Control
Bit
7
6
5
4
3
2
1
0
Name XCLKVLD
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; SFR Page = All Pages
Bit
Name
Function
7 XCLKVLD External Oscillator Valid Flag.
Provides External Oscillator status and is valid at all times for all modes of opera-
tion 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[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.
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 RC mode.
Set according to the desired K Factor for C mode.
XFCN
000
001
010
011
100
101
110
111
Crystal Mode
f 20 kHz
20 kHz f 58 kHz
58 kHz f 155 kHz
155 kHz f 415 kHz
415 kHz f 1.1 MHz
1.1 MHz f 3.1 MHz
3.1 MHz f 8.2 MHz
8.2 MHz f 25 MHz
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
152
Rev. 1.4
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