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Newsgroups: comp.lang.ada
Date: Tue, 28 Jan 2020 14:06:28 -0800 (PST)
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Subject: Re: GNATCOLL-Mmap example
From: Bob Goddard <1963bib@googlemail.com>
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Xref: reader01.eternal-september.org comp.lang.ada:57980
Date: 2020-01-28T14:06:28-08:00
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On Tuesday, 28 January 2020 20:18:03 UTC, Philip Munts  wrote:
[...]
> Here is a quick example using libsimpleio:
> 
> WITH GPIO.libsimpleio;
> WITH RaspberryPi;
> 
> PROCEDURE test_gpio IS
> 
>   outp : CONSTANT GPIO.Pin :=
>     GPIO.libsimpleio.Create(RaspberryPi.GPIO18, GPIO.Output);
> 
> BEGIN
>   LOOP
>     outp.Put(True);
>     outp.Put(False);
>   END LOOP;
> END test_gpio;
> 
> On a Raspberry Pi 4, which is what happens to be plugged in today, I measured a 360 kHz square wave at GPIO 18.  Never mess around with memory mapped I/O unless you need insanely high performance.  Then you would probably want to use DMA anyway.

Think I'll use that as a backup, but go down the ioctl route, it is a learning process after all...