Sfr Definition 21.6. Oscxcn: External Oscillator Control - Silicon Laboratories C8051T620 Manual

SFR Definition 21.6. OSCXCN: External Oscillator Control

Bit 7
Name XCLKVLD
R
Type
0
Reset
SFR Address = 0xB1
Bit Name
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.
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 RC mode.
Set according to the desired K Factor for C mode.
XFCN
000
001
010
011
100
101
110
111
C8051T620/1/6/7 & C8051T320/1/2/3
6 5 4
XOSCMD[2:0]
R/W
0 0 0
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
Rev. 1.2
3 2
- XFCN[2:0]
R
0 0
Function
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
1 0
R/W
0 0
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
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