C8051F537-IM Silicon Laboratories Inc, C8051F537-IM Datasheet - Page 141

• Manufacturer Part Number: C8051F537-IM
• Description: IC 8051 MCU 2K FLASH 20QFN
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F53xr

Specifications of C8051F537-IM

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 16
• Program Memory Size: 2KB (2K x 8)
• Program Memory Type: FLASH
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.25 V
• Data Converters: A/D 16x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 20-QFN
• Data Bus Width: 8 bit
• Data Ram Size: 256 B
• Interface Type: SPI, UART
• Maximum Clock Frequency: 25 MHz
• Number Of Programmable I/os: 16
• Number Of Timers: 3
• Operating Supply Voltage: 2.7 V to 5.25 V
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 12 bit, 16 Channel
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details
• Other names: 336-1400

SFR Definition 14.4. OSCXCN: External Oscillator Control
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 Reserved
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 = 0b; Must write 0b.
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 = Pullup 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
DD
XFCN
R/W
000
001
010
011
100
101
110
Bit6
111
= Power Supply on MCU in volts
3
) / (R x C), where
Crystal (XOSCMD = 11x)
DD
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
R/W
Bit5
58 kHz  f 155 kHz
20 kHz f 58 kHz
), where
f  20 kHz
R/W
Bit4
C8051F52x/F52xA/F53x/F53xA
Rev. 1.3
R/W
Bit3
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
XFCN2
f 25 kHz
R/W
Bit2
XFCN1
R/W
Bit1
SFR Address:
C (XOSCMD = 10x)
XFCN0
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
R/W
Bit0
00000000
Reset Value
0xB1
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