C8051F545-IQR Silicon Labs, C8051F545-IQR Datasheet - Page 146

• Manufacturer Part Number: C8051F545-IQR
• Description: 8-bit Microcontrollers - MCU 50 MIPS 8 kB 1 kB SPI UART I2C
• Manufacturer: Silicon Labs

Specifications of C8051F545-IQR

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

C8051F54x
Equation 17.2. C Mode Oscillator Frequency






f
=
KF
R V
DD
For example: Assume V
= 2.1 V and f = 75 kHz:
DD
f = KF / (C x VDD)
0.075 MHz = KF / (C x 2.1)
Since the frequency of roughly 75 kHz is desired, select the K Factor from the table in SFR Definition 17.6
(OSCXCN) as KF = 7.7:
0.075 MHz = 7.7 / (C x 2.1)
C x 2.1 = 7.7 / 0.075 MHz
C = 102.6 / 2.0 pF = 51.3 pF
Therefore, the XFCN value to use in this example is 010b.
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