C8051F120DK Silicon Laboratories Inc, C8051F120DK Datasheet - Page 189

• Manufacturer Part Number: C8051F120DK
• Description: DEVKIT-F120/21/22/23/24/25/26/27
• Manufacturer: Silicon Laboratories Inc
• Type: MCUr

Specifications of C8051F120DK

• Contents: Evaluation Board, Power Supply, USB Cables, Adapter and Documentation
• Processor To Be Evaluated: C8051F12x and C8051F13x
• Interface Type: USB
• Silicon Manufacturer: Silicon Labs
• Core Architecture: 8051
• Silicon Core Number: C8051F120
• Silicon Family Name: C8051F12x
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: C8051F120, 121, 122, 123, 124, 125, 126, 127
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1224

Bit7:
Bits6–4: XOSCMD2–0: External Oscillator Mode Bits.
Bit3:
Bits2–0: XFCN2–0: External Oscillator Frequency Control Bits.
CRYSTAL MODE (Circuit from Figure 14.1, Option 1; XOSCMD = 11x)
RC MODE (Circuit from Figure 14.1, Option 2; XOSCMD = 10x)
C MODE (Circuit from Figure 14.1, Option 3; XOSCMD = 10x)
XTLVLD XOSCMD2 XOSCMD1 XOSCMD0
Bit7
R
XTLVLD: Crystal Oscillator Valid Flag.
( Valid only when XOSCMD = 11x. )
0: Crystal Oscillator is unused or not yet stable.
1: Crystal Oscillator is running and stable.
00x: External Oscillator circuit off.
010: External CMOS Clock Mode (External CMOS Clock input on XTAL1 pin).
011: External CMOS Clock Mode with divide by 2 stage (External CMOS Clock input on
XTAL1 pin).
10x: RC/C Oscillator Mode with divide by 2 stage.
110: Crystal Oscillator Mode.
111: Crystal Oscillator Mode with divide by 2 stage.
RESERVED. Read = 0, Write = don't care.
000-111: see table below:
Choose XFCN value to match crystal frequency.
Choose XFCN value to match frequency range:
f = 1.23(10
f = frequency of oscillation in MHz
C = capacitor value in pF
R = Pullup resistor value in k 
Choose K Factor (KF) for the oscillation frequency desired:
f = KF / (C * V
f = frequency of oscillation in MHz
C = capacitor value on XTAL1, XTAL2 pins in pF
V
XFCN
DD
000
001
010
100
101
011
110
111
SFR Definition 14.4. OSCXCN: External Oscillator Control
= Power Supply on MCU in Volts
R/W
Bit6
3
Crystal (XOSCMD = 11x)
) / (R * C) , where
590 kHz  f  1.5 MHz
225 kHz  f  590 kHz
10 MHz  f  30 MHz
84 kHz  f  225 kHz
1.5 MHz  f  4 MHz
DD
4 MHz  f  10 MHz
32 kHz  f  84 kHz
R/W
) , where
Bit5
f  32 kHz
R/W
Bit4
Rev. 1.4
800 kHz  f  1.6 MHz
1.6 MHz  f  3.2 MHz
100 kHz  f  200 kHz
200 kHz  f  400 kHz
400 kHz  f  800 kHz
RC (XOSCMD = 10x)
Bit3
50 kHz  f  100 kHz
25 kHz  f  50 kHz
R
-
C8051F120/1/2/3/4/5/6/7
f  25 kHz
XFCN2
R/W
Bit2
C8051F130/1/2/3
XFCN1
R/W
Bit1
C (XOSCMD = 10x)
K Factor = 1590
K Factor = 0.87
K Factor = 180
K Factor = 664
K Factor = 2.6
K Factor = 7.7
K Factor = 22
K Factor = 65
SFR Address:
XFCN0
SFR Page:
R/W
Bit0
0x8C
F
00000000
Reset Value
189