C8051F331 Silicon Laboratories Inc, C8051F331 Datasheet - Page 107

• Manufacturer Part Number: C8051F331
• Description: IC 8051 MCU 8K FLASH 20MLP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F33xr

Specifications of C8051F331

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: SMBus (2-Wire/I²C), SPI, UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 17
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-QFN
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Data Converters: -

Bit7:
Bits6-4:
Bit3:
Bits2-0:
CRYSTAL MODE (Circuit from Figure 13.1, Option 1; XOSCMD = 11x)
RC MODE (Circuit from Figure 13.1, Option 2; XOSCMD = 10x)
C MODE (Circuit from Figure 13.1, 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.
XOSCMD2-0: External Oscillator Mode Bits.
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.
XFCN2-0: External Oscillator Frequency Control Bits.
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 clock in MHz
C = capacitor value in pF
R = Pull-up resistor value in kΩ
Choose K Factor (KF) for the oscillation frequency desired:
f = KF / (C *
f = frequency of clock in MHz
C = capacitor value the XTAL2 pin in pF
V
DD = Power Supply on MCU in volts
XFCN
000
001
010
100
101
011
110
111
R/W
Bit6
Figure 13.5. OSCXCN: External Oscillator Control Register
3
) / (R * C), where
V
Crystal (XOSCMD = 11x)
DD ), where
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
Bit5
f ≤ 32 kHz
R/W
Bit4
C8051F330/1, C8051F330D
Rev. 1.2
Bit3
R
-
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)
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
107