C8051F34A-GMR Silicon Labs, C8051F34A-GMR Datasheet - Page 137

• Manufacturer Part Number: C8051F34A-GMR
• Description: 8-bit Microcontrollers - MCU 48 MIPS 64KB 10ADC
• Manufacturer: Silicon Labs

Specifications of C8051F34A-GMR

• Rohs: yes
• Core: 8051
• Processor Series: C8051
• Data Bus Width: 8 bit

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.
(Read 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.
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.
RESERVED. Read = 0, Write = don't care.
000-111: See table below:
Choose XFCN value to match crystal or resonator frequency.
Choose XFCN value to match frequency range:
f = 1.23(10
f = frequency of clock in MHz
C = capacitor value in pF
R = Pull-up resistor value in k 
Choose K Factor (KF) for the oscillation frequency desired:
f = KF / (C x V
f = frequency of clock in MHz
C = capacitor value the XTAL2 pin in pF
V
XFCN Crystal (XOSCMD = 11x) RC (XOSCMD = 10x)
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
590 kHz  f  1.5 MHz
225 kHz  f  590 kHz
10 MHz  f  30 MHz
3
84 kHz  f  225 kHz
1.5 MHz  f  4 MHz
4 MHz  f  10 MHz
) / (R x C) , where
32 kHz  f  84kHz
DD
R/W
f  32 kHz
Bit5
) , where
C8051F340/1/2/3/4/5/6/7/8/9/A/B/C/D
R/W
Bit4
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
Rev. 1.3
25 kHz  f  50 kHz
Bit3
R
-
f  25 kHz
XFCN2
R/W
Bit2
XFCN1
C (XOSCMD = 10x)
R/W
Bit1
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
XFCN0
R/W
Bit0
SFR Address:
00000000
Reset Value
0xB1
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