Re: Strange 8255 behavior

From: smf <smf_at_null.net>
Date: Sun, 10 Jun 2018 12:18:50 +0100
Message-ID: <07638161-c990-d807-25d7-fef2c5458c7c@null.net>
On 10/06/2018 10:57, André Fachat wrote:

> I find it amazing what chip designers sometimes do that really annoy 
> the programmers or users. And this sometimes even means additional 
> hardware so it can't be attributed to scarcity of resources  (like I 
> guess clearing interrupt flags by just reading the flags....).

I assume for cost purposes they don't keep the last output value when in 
read mode, so when you switch back to output mode then zeros is probably 
the lesser of two evils.

Trying to replace a mos chip with an intel chip is blasphemy :-)
Received on 2018-06-10 14:00:05

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