Samsung S3C84I8 User Manual page 224

S3C84I8/F84I8/C84I9/F84I9
7
CLOCK CIRCUIT
OVERVIEW
The clock frequency generated for the Main clock of S3C84I8/F84I8/C84I9/F84I9 by an external crystal can range
from 1 MHz to 10 MHz. The maximum CPU clock frequency is 10 MHz. The X
external oscillator or clock source to the on-chip clock circuit. Also the subsystem clock frequency for the Watch
timer by an external crystal can range from 30KHz to 35KHz. The XT
oscillator or clock source to the on-chip clock circuit.
SYSTEM CLOCK CIRCUIT
The system clock circuit has the following components:
— External crystal or ceramic resonator oscillation source (or an external clock source)
— Oscillator stop and wake-up functions
— Programmable frequency divider for the CPU clock (fxx divided by 1, 2, 8, or 16)
— System clock control register, CLKCON
— Oscillator control register, OSCCON and STOP control register, STPCON
C1
C2
Figure 7-1. Main Oscillator Circuit
(Crystal or Ceramic Oscillator)
X
IN
S3C84I8/S3F84I8
S3C84I9/S3F84I9
X
OUT
and X
IN OUT
and XT pins connect the external
IN OUT
32.768 kHz
Figure 7-2. Sub-System Oscillator Circuit
(Crystal Oscillator)
CLOCK CIRCUIT
pins connect the
XT
IN
S3C84I8/S3F84I8
S3C84I9/S3F84I9
XT
OUT
7-1