c8051t623-g Silicon Laboratories, c8051t623-g Datasheet - Page 89

• Manufacturer Part Number: c8051t623-g
• Description: Full Speed Usb Eprom Mcu Family
• Manufacturer: Silicon Laboratories

C8051T622/3 and C8051T326/7
SFR Definition 16.6. OSCXCN: External Oscillator Control
SFR Address = 0xB1
96
Name XCLKVLD
Reset
6:4
2:0
Bit
Type
7
3
Bit
XOSCMD[2:0] External Oscillator Mode Select.
XFCN[2:0]
XCLKVLD
Unused
Name
R
7
0
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.
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.
Read = 0; Write = Don’t Care
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
100
101
110
011
111
6
0
XOSCMD[2:0]
415 kHz f 1.1 MHz
1.1 MHz f 3.1 MHz
3.1 MHz f 8.2 MHz
155 kHz f 415 kHz
8.2 MHz f 25 MHz
58 kHz f 155 kHz
20 kHz f 58 kHz
Crystal Mode
R/W
5
0
f 20 kHz
Rev. 1.1
4
0
1.6 MHz f 3.2 MHz
100 kHz f 200 kHz
200 kHz f 400 kHz
400 kHz f 800 kHz
800 kHz f 1.6 MHz
50 kHz f 100 kHz
25 kHz f 50 kHz
Function
R
3
0
-
f 25 kHz
RC Mode
2
0
XFCN[2:0]
K Factor = 1590
R/W
K Factor = 0.87
K Factor = 180
K Factor = 664
K Factor = 2.6
K Factor = 7.7
K Factor = 22
K Factor = 65
1
0
C Mode
0
0