Why Doesn't the E5 Crystal Oscillator
Amplifier Work?

If it appears that the E5' crystal oscillator amplifier is not working in your application, check these items.

Is the E5 Device Initialized?

The E5's crystal oscillator amplifier must first be initialized before it starts to operate.  The E5 uses its internal ring oscillator as the clock source until it loads its initialization boot data.  Until the E5 is initialized, the crystal oscillator amplifier does not function.

Are the E5 Configuration Options Set Correctly?

Check the configuration options for your design in FastChip Device Link.  Click the Configuration button.  Click the Crystal between XTALIN and XTAL option.  Enter the crystal's operating Frequency in MHz.  Ensure that there is sufficient Settling Time or start-up time for your specific crystal component.  Check the Use Feedback Resistor option.

I-M-P-O-R-T-A-N-T The crystal will not oscillate unless you select the Use Feedback Resistor option.  In FastChip 2.3.0 and earlier, this option was off by default.  Future versions of FastChip will select this option by default.

Is the External Crystal Compensation Circuitry Correct?

If the problem occurs on your own E5 target hardware, double-check the external compensation circuitry.  The E5 operates with a variety of crystal types and vendors but the compensation circuitry must match these values.

Crystal Frequency Range	Suggested External Resistor (R1)	External Capacitor (C1 and C2)
32.768 kHz	10 MW	10 pF
2 MHz—24 MHz (fundamental)	1 MW
24 MHz—40 MHz (third overtone)	4.7 kW

FastChip Version: 2.3.0

This solution may or may not apply to other versions of the FastChip development system.

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