C8051F305-GSR Silicon Labs, C8051F305-GSR Datasheet - Page 100

• Manufacturer Part Number: C8051F305-GSR
• Description: 8-bit Microcontrollers - MCU 2KB 14Pin MCU
• Manufacturer: Silicon Labs

Specifications of C8051F305-GSR

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

C8051F300/1/2/3/4/5
100
Bit7:
Bits6–4: XOSCMD2-0: External Oscillator Mode Bits.
Bit3:
Bits2–0: XFCN2-0: External Oscillator Frequency Control Bits.
CRYSTAL MODE (Circuit from Figure 11.1, Option 1; XOSCMD = 11x)
RC MODE (Circuit from Figure 11.1, Option 2; XOSCMD = 10x)
C MODE (Circuit from Figure 11.1, 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 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.
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 = Pull-up resistor value in k
Choose K Factor (KF) for the oscillation frequency desired:
f = KF / (C x V
f = frequency of oscillation in MHz
C = capacitor value the XTAL2 pin in pF
V
DD
XFCN
SFR Definition 11.3. OSCXCN: External Oscillator Control
000
001
010
100
101
011
110
111
= Power Supply on MCU in volts
R/W
Bit6
3
) / (R x C), where
Crystal (XOSCMD = 11x)
DD
225 kHz  f 590 kHz
590 kHz  f 1.5 MHz
10 MHz  f 30 MHz
84 kHz  f 225 kHz
1.5 MHz  f 4 MHz
4 MHz  f 10 MHz
32 kHz f 84 kHz
R/W
), where
Bit5
f  32 kHz
R/W
Bit4
Rev. 2.9
Bit3
—
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
R
RC (XOSCMD = 10x)
50 kHz f 100 kHz
25 kHz f 50 kHz
f 25 kHz
XFCN2
R/W
Bit2
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
XFCN0
R/W
Bit0
SFR Address:
00000000
Reset Value
0xB1