Messages in this thread | | | Date | Fri, 17 Feb 2006 21:39:03 +0000 | From | Russell King <> | Subject | Re: [PATCH] SIIG 8-port serial boards support |
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On Fri, Feb 17, 2006 at 03:27:44PM -0600, Paul Fulghum wrote: > Russell King wrote: > >So, there are three distinct flow control scenarios: > > So I'm clear on how you interpret these, > am I correct with the following? > > >- conventional RTS/CTS > RTS active = ready to receive > CTS active = allowed to send > > >- alternative RTS/CTS > RTS active = on before send, off after send > CTS active = allowed to send
I'll have to dig through my archives to confirm this one.
> >- RS485 > RTS active = on before send, off after send (RTS enables driver) > CTS ignored (2 wire mode, no CTS) > > So maybe the extra control fields would be: > CRTSONTX - RTS on before send, off after send > CTXONCTS - wait for CTS before sending
That's a possibility, except that programs today expect CRTSCTS to enable RTS/CTS flow control.
What I suggest is to use CRTSCTS to enable the chosen flow control method. Then we have a set of cflag bits which describe the flow control mode, eg CFLOWRS485, CFLOWMODEM, CFLOWALT (probably needs better names.) CFLOWMODEM being the conventional mode should have an all zeros value.
-- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 Serial core - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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