C8051T630DK Silicon Laboratories Inc, C8051T630DK Datasheet - Page 101

• Manufacturer Part Number: C8051T630DK
• Description: KIT DEV FOR C8051T630 FAMILY
• Manufacturer: Silicon Laboratories Inc
• Type: MCUr

Specifications of C8051T630DK

• Contents: Board, daughter boards, power adapter, cables, documentation and software
• Processor To Be Evaluated: C8051T63x
• Interface Type: USB
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: C8051T630, T631, T632, T633, T634 and T635 MCUs
• For Use With: 336-1465 - BOARD SOCKET DAUGHTER 20-QFN
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1464

19. Oscillators and Clock Selection
C8051T630/1/2/3/4/5 devices include a programmable internal high-frequency oscillator, a programmable
internal low-frequency oscillator, and an external oscillator drive circuit. The internal high-frequency oscilla-
tor can be enabled/disabled and calibrated using the OSCICN and OSCICL registers, as shown in
Figure 19.1. The internal low-frequency oscillator can be enabled/disabled and calibrated using the
OSCLCN register. The system clock can be sourced by the external oscillator circuit or either internal oscil-
lator. Both internal oscillators offer a selectable post-scaling feature.
19.1. System Clock Selection
The CLKSL[1:0] bits in register CLKSEL select which oscillator source is used as the system clock.
CLKSL[1:0] must be set to 01b for the system clock to run from the external oscillator; however the exter-
nal oscillator may still clock certain peripherals (timers, PCA) when the internal oscillator is selected as the
system clock. The system clock may be switched on-the-fly between the internal oscillator, external oscilla-
tor, and Clock Multiplier so long as the selected clock source is enabled and running.
The internal high-frequency and low-frequency oscillators require little start-up time and may be selected
as the system clock immediately following the register write which enables the oscillator. The external RC
and C modes also typically require no startup time.
CMOS Mode
C Mode
EXTCLK
VDD
RC Mode
EXTCLK
EXTCLK
EXTCLK
Figure 19.1. Oscillator Options
OSCICL
Circuit
OSCLF
Low Frequency
Input
Programmable
Internal Clock
Generator
OSCXCN
Oscillator
Rev. 1.0
OSC
EN
EN
OSCICN
C8051T630/1/2/3/4/5
OSCLD
n
n
CLKSEL
OSCLCN
OSCLF OSCLD
SYSCLK
101