C8051F340 Datasheet, PDF (135/282 Pages) List of Unclassifed Manufacturers – Full Speed USB Flash MCU Family

C8051F340/1/2/3/4/5/6/7
14. Oscillators
C8051F340/1/2/3/4/5/6/7 devices include a programmable internal high-frequency oscillator, a program-
mable internal low-frequency oscillator (C8051F340/1/2/3/4/5), an external oscillator drive circuit, and a 4x
Clock Multiplier. The internal high-frequency and low-frequency oscillators can be enabled/disabled and
adjusted using the special function registers, as shown in Figure 14.1. The system clock (SYSCLK) can be
derived from either of the internal oscillators, the external oscillator circuit, or the 4x Clock Multiplier divided
by 2. The USB clock (USBCLK) can be derived from the internal oscillator, external oscillator, or 4x Clock
Multiplier. Oscillator electrical specifications are given in Table 14.1.
OSCICL
OSCICN
OSCLCN
CLKSEL
Option 2
VDD
XTAL2
Option 3
XTAL2
Option 1
XTAL1
10MΩ
XTAL2
Option 4
XTAL2
EN
Programmable High- ^IOSC
n
Frequency Oscillator
OSCLF3-0
EN
n
Programmable Low-
Frequency Oscillator
(C8051F340/1/2/3/4/5)
Input
Circuit
EXOSC
OSC
IOSC
OSCXCN
EXOSC
EXOSC / 2
CLKMUL
x2
x2
Clock Multiplier
IOSC / 2
EXOSC
EXOSC / 2
EXOSC / 3
EXOSC / 4
SYSCLK
USBCLK
Figure 14.1. Oscillator Diagram
Rev. 0.5
135