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<== Date ==> <== Thread ==>

Subject: Re: Greenspring rs422 support
From: Andrew Johnson <[email protected]>
To: "Peregrine M. McGehee" <[email protected]>
Cc: [email protected]
Date: Wed, 11 Mar 1998 17:16:15 +0000
Marty Kraimer wrote:
> 
> When you enable the transmit interrupt an interrupt will occur as soon
> as the 1 character transmit buffer is empty, i.e. almost always
> immediately.

There are serial chips which will only generate an interrupt if
interrupts are enabled when the transmit buffer *goes* empty.  A driver
for these would have to output the first character from the Write
function, and this is why some drivers work this way.  However, if the
chip you have will do it, the approach Marty describes is much cleaner.

-- Andrew
   ___
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+----------	WWW: http://www.ast.cam.ac.uk/~anj

References:
Re: Greenspring rs422 support Peregrine M. McGehee
Re: Greenspring rs422 support Marty Kraimer

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