Calling Line Identifier

FX602

© 1998 Consumer Microcircuits Limited

13

D/602/7

1.5.9

Xtal Osc and Clock Dividers

Frequency and timing accuracy of the FX602 is determined by a 3.579545MHz clock present at the XTAL pin.

This may be generated by the on-chip oscillator inverter using the external components C1, C2 and X1 of

Figure 2, or may be supplied from an external source to the XTAL input, in which case C1, C2 and X1 should

not be fitted.

The oscillator is turned off in the 'Zero-Power' modes.

If the clock is provided by an external source which is not always running, then the ZP input must be set high

when the clock is not available. Failure to observe this rule may cause a significant rise in the supply current

drawn by FX602 as well as generating undefined states of the RXD, DET and IRQN outputs.