Cirrus-logic CS5368 Manuel d'utilisateur télécharger pdf (Page 20)

20 DS624F5

CS5368

4.3 Master Clock Source

The CS5368 requires a Master Clock that can come from one of two sources: an on-chip crystal oscillator

driver or an externally generated clock.

4.3.1 On-Chip Crystal Oscillator Driver

When using the on-board crystal oscillator driver, the XTI pin (pin 21) is the input for the Master Clock (MC-

LK) to the device. The XTO pin (pin 22) must not be used to drive anything other than the oscillator tank

circuitry. When using the on-board crystal driver, the topology shown in Figure 7 must be used. The crystal

oscillator manufacturer supplies recommended capacitor values. A buffered copy of the XTI input is avail-

able as an output on the MCLK pin (pin 23), which is level-controlled by VLS and may be used to synchro-

nize other parts to the device.

Figure 7. Crystal Oscillator Topology

4.3.2 Externally Generated Master Clock

If an external clock is used, the XTI and XTO pins must be grounded, and the MCLK pin becomes an input

for the system master clock. The incoming MCLK should be at the logic level set by the user on the VLS

supply pin.

XTI

XTO

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Cirrus-logic CS5368 Manuel d'utilisateur Page 20