ECIO crystal frequency

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kirstom14
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ECIO crystal frequency

Postby kirstom14 » Tue Jul 27, 2010 5:00 pm

Sorry if this sounds stupid. But I am using the ECIO-40P, and for my application the crystal is too fast.
What can I do to decrease the crystal frequency to about 16MHz?? I need to use USB communication also.
When reducing the frequency can I still use the USB (D+, D-)?

Thanks
tomcat14

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Benj
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Re: ECIO crystal frequency

Postby Benj » Wed Jul 28, 2010 8:38 am

Hello,

Sorry you cannot use the USB if you lower the frequency as it needs a 48MHz clock to allow it to run at the USB speed of 12MIPs. Why do you need the chip to run slower? maybe there is a good alternative.

kirstom14
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Re: ECIO crystal frequency

Postby kirstom14 » Wed Jul 28, 2010 11:29 am

Hi,

I need to have a PWM frequency which is less than 200Hz, which I cannot achieve.

If I build the circuit myself, and dumping a boot-loader in the PIC will I still be able to program it
like I program the ECIO, using the "Compile to Chip" button? As if this is possible it would solve my problem.

Thanks
tomcat14

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Re: ECIO crystal frequency

Postby Benj » Wed Jul 28, 2010 4:34 pm

Hello,

There is an example available here that shows how to create a timer controlled PWM output. This could be at pretty much any frequency that you require.

viewtopic.php?f=26&t=6732