C8051F351 Silicon Laboratories Inc, C8051F351 Datasheet - Page 125

• Manufacturer Part Number: C8051F351
• Description: IC 8051 MCU 8K FLASH 28MLP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F35xr

Specifications of C8051F351

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 50MHz
• Connectivity: SMBus (2-Wire/I²C), SPI, UART/USART
• Peripherals: POR, PWM, Temp Sensor, 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
• Data Converters: A/D 8x24b; D/A 2x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-VQFN Exposed Pad, 28-HVQFN, 28-SQFN, 28-DHVQFN
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -

17.
C8051F350/1/2/3 devices include a programmable internal oscillator, an external oscillator drive circuit,
and a clock multiplier. The internal oscillator can be enabled/disabled and calibrated using the OSCICN
and OSCICL registers, as shown in Figure 17.1. The system clock (SYSCLK) can be derived from the
internal oscillator, external oscillator circuit, or the clock multiplier. The clock multiplier can produce three
possible outputs: Internal Oscillator x 2, External Oscillator x 2, or External Oscillator x 4. Oscillator electri-
cal specifications are given in Table 17.1 on page 131.
17.1. Programmable Internal Oscillator
All C8051F350/1/2/3 devices include a programmable internal oscillator that defaults as the system clock
after a system reset. The internal oscillator period can be programmed via the OSCICL register, shown in
Figure 17.3. On C8051F350/1/2/3 devices, OSCICL is factory calibrated to obtain a 24.5 MHz frequency.
Electrical specifications for the precision internal oscillator are given in Table 17.1 on page 131. Note that
the system clock may be derived from the programmed internal oscillator divided by 1, 2, 4, or 8, as
defined by the IFCN bits in register OSCICN. The divide value defaults to 8 following a reset.
VDD
Option 2
XTAL2
Oscillators
Option 1
Option 4
10MΩ
XTAL2
Option 3
XTAL2
XTAL1
XTAL2
Figure 17.1. Oscillator Diagram
OSCICL
Circuit
Input
Programmable
Internal Clock
Generator
OSCXCN
OSC
EN
Rev. 0.4
EXOSC / 2
OSCICN
IOSC
EXOSC
EXOSC
IOSC/2
CLKMUL
n
Clock Multiplier
x4
C8051F350/1/2/3
CLKSEL
SYSCLK
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