Samsung S3F80JB manual Clock Circuits, System Clock Circuit

S3F80JB CLOCK CIRCUITS

7 CLOCK CIRCUITS

OVERVIEW

The clock frequency for the S3F80JB can be generated by an external crystal or supplied by an external clock source. The clock frequency for the S3F80JB can range from 1MHz to 8 MHz. The maximum CPU clock frequency, as determined by CLKCON register, is 8 MHz. The XIN and XOUT pins connect the external 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)

—Oscillator stop and wake-up functions

—Programmable frequency divider for the CPU clock (fOSC divided by 1, 2, 8, or 16)

—Clock circuit control register, CLKCON

C1 XIN

C2 XOUT

External XIN Clock

Open Pin

XOUT

Figure 7-1. Main Oscillator Circuit	Figure 7-2. External Clock Circuit
(External Crystal or Ceramic Resonator)

7-1