External clocking a serial port?

External clocking a serial port?

[DeRobertis]

To run a Mac serial port at 1.8Mbps like the Epson Stylus Color 740's
docs say it can, you need external clocking.

I'm guessing the Stylus Color 740 is sending out the proper clock to do
so -- and no doubt that would take out Linux using the crtscts option!
The clock input and remote side ready just happen to occupy the same
pin. That would explain it flapping the ready so many times per second.

How do I turn on external clocking under linux?


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Re: External clocking a serial port?

[Giuliano Pochini]

DeRobertis wrote:
>
> To run a Mac serial port at 1.8Mbps like the Epson Stylus Color 740's
> docs say it can, you need external clocking.
>
> I'm guessing the Stylus Color 740 is sending out the proper clock to do
> so -- and no doubt that would take out Linux using the crtscts option !

Hmm, It's possible...

> The clock input and remote side ready just happen to occupy the same
> pin. That would explain it flapping the ready so many times per second.
>
> How do I turn on external clocking under linux?

You have to hack the driver:

[macserial.h]

#define EXTSYNC         0x30    /* External Sync Mode */

and

/* Write Register 11 (Clock Mode control) */


Bye.


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