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Re: Master Clock

The data sheet of ETRAX 100LX, specifies the external master clock to 
20 MHz +/- 2%, but in practice it will run at somewhat lower frequencies 
too. The Ethernet and USB interfaces will however not work unless you have
less than 100 PPM deviation from 20 MHz.

There is a possibility to use a separate  external clock input for the
serial port baud rate. The external baud rate clock is input on pin pb6
(ball Y19). The baud rate will be the external baud rate clock divided 
by 8. (There is also a possibility to use an internal timer to divide the 
external baud rate clock, but this last alternative is not so useful since
it gives different baud rates for the receiver and transmitter.)

I don't know if the external baud rate clock option is supported in the 
Linux drivers.

Per Zander

On Wed, 20 Nov 2002, Leonardo Salomone wrote:

> Is it possible to use a different external master clock on the 
> ETRAX100LX MCM (say lower than 20Mhz) to achieve an exact baud rate?
> Thanks
> Leo Salomone
> leos@xxxxxxx.com