CAM35C44 datasheet(12/50 Pages) SMSC

12 / 50 page

CLOCK GENERATOR

An internal 3.3v crystal oscillator or an external

oscillator source is required for the CAM35C44

(FIGURE 3). The crystal/clock pins and buffer

types are shown in TABLE 1.

The X1/CLK1 and X2 pins provide an external

connection for a parallel resonant 24MHz crystal.

Configuration register CR08 bit 5, INT_OSC,

must be set to “1” to configure the internal

oscillator for this arrangement (see the section

CRO8 - Power Control on page 27).

An external CMOS compatible oscillator is

required if a 24MHz crystal is not used. In this

case INT_OSC must be set to “0”.

The X2 pin is the 24MHz crystal driver and

should not be used to drive any other device.

This pin should be left unconnected if an

external clock is used and INT_OSC is “0”.

The 24MHz crystal can be used to directly drive

the ACE block.

This saves power when

115.2Kbps or slower data transfers are required

because the PLL and SCE block do not need to

be powered.

See TABLE 25 and the section

CRO8 - Power Control on page 27.

FIGURE 3 - EXAMPLE 24MHz OSCILLATOR CIRCUIT

CAM35C44

X1/CLK1

24MHz CRYSTAL

CAM35C44 데이터시트(PDF) 12 Page - SMSC Corporation