Messages in this thread | | | From | Alexander Stein <> | Subject | Re: [PATCH] Documentation about RS485 serial communications | Date | Tue, 19 Oct 2010 17:27:27 +0200 |
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On Tuesday 19 October 2010, 16:29:48 Grant Edwards wrote: > On 2010-10-19, Claudio Scordino <claudio@evidence.eu.com> wrote: > > +2. HARDWARE-RELATED CONSIDERATIONS > > + > > + Some CPUs (e.g., Atmel AT91) contain a transceiver capable of working > > both + as RS232 and RS485. > > Pardon my curiosity, but I've looked at a few AT91 parts, and I've > never seen on with an internal transceiver -- nor does Google seem > able to find any. > > Frankly, I'd be pretty surprised, since it would be very difficult > (fab-wise), to build a mircoprocessor with I/O cells capable of > withstanding the voltage levels specified in RS232. > > Can you specify to which parts you're referring?
I doubt the AT91 do have an internal transceiver but it has a dedicated pin feature (RTS or CTS or something) which can be used to switch between RS232 and RS485 by setting a bit in the USART provided the pin is connected properly.
Regards, Alexander
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