c8051t617 Silicon Laboratories, c8051t617 Datasheet - Page 110

• Manufacturer Part Number: c8051t617
• Description: Mixed Signal Byte-programmable Eprom Mcu
• Manufacturer: Silicon Laboratories

C8051T610/1/2/3/4/5/6/7
13. Oscillators
C8051T61x devices include a programmable internal oscillator and an external oscillator drive circuit. The
internal oscillator can be enabled/disabled and calibrated using the OSCICN and OSCICL registers, as
shown in Figure 13.1. The system clock can be sourced by the external oscillator circuit, the internal oscil-
lator, or a scaled version of the internal oscillator. The internal oscillator's electrical specifications are given
in Table 13.1 on page 112.
13.1. Calibrated Internal Oscillator
All C8051T61x devices include a calibrated internal oscillator that defaults as the system clock after a sys-
tem reset. The oscillator is factory calibrated to obtain a 24.5 MHz frequency at room temperature, using
the OSCICL register.
Electrical specifications for the precision internal oscillator are given in Table 13.1 on page 112. 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.
110
VDD
Option 3
Option 2
EXTCLK
EXTCLK
Option 1
EXTCLK
Figure 13.1. Oscillator Diagram
EXTCLK
Rev. 0.3
OSCICL
Circuit
Programmable
Input
Internal Clock
Generator
EXTCLK
OSC
EN
OSCICN
n
CLKSEL
SYSCLK