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From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Bidirectional UART design for Ravenscar
Date: Fri, 25 Aug 2017 23:24:38 +0100
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Date: 2017-08-25T23:24:38+01:00
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I'm trying to implement a two-way interrupt-driven interface via a UART
with Ravenscar, and having trouble because there is one interrupt with
multiple causes; a writer must wait until transmission is possible
before putting the next character, while a reader must wait until
there's a character to be read.

This makes it hard to write a PO with a single entry (a Ravenscar
restriction) that serves both requirements.

It occurs to me that the interrupt handler could release one of two
suspension objects; if it's Tx_Transfer_Complete, release the SO that
the writer waits on, if it's Rx_Transfer_Complete release the reader's
SO.

Does that seem a reasonable approach?