Samsung S3C80M4/F80M4 User Manual page 191

S3C80M4/F80M4 CLOCK CIRCUIT
7
CLOCK CIRCUIT
OVERVIEW
The clock frequency generated for the S3C80M4/F80M4 by an external crystal can range from 0.4 MHz to 10
MHz. The maximum CPU clock frequency is 10 MHz. The X and X pins connect the external oscillator or
IN OUT
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
— Clock output control register, CLOCON
— STOP control register, STPCON
CPU CLOCK NOTATION
In this document, the following notation is used for descriptions of the CPU clock;
fx: main clock
fxx: selected system clock
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