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Re: [avr-gcc-list] Thanks

From: J Wunsch
Subject: Re: [avr-gcc-list] Thanks
Date: Fri Jan 12 22:40:05 2001

Dale Seaburg <address@hidden> wrote:

> A big thanks to Jason, Carl and especially to Joerg.

Oh, don't forget Denis.  Without his work, we wouldn't have something
to talk about in this mailing list at all. ;-)  The presence of avr-gcc
was my prime reason to chose AVR for future microcontroller projects.

> However, that one (uisp) was a bit tricky.  I had to go into the DAPA.C
> file and hand edit the #defines because it could not find my lp.h
> include file, or so it seems.  [...]

uisp is indeed tricky.  I started porting it to FreeBSD, but i
eventually gave up.  FreeBSD offers a more abstracted layer to access
the parallel port, called `ppi'.  This driver doesn't require
superuser privileges, and it cooperates with other potential users of
the parallel port, i. e. the printer spooler wouldn't have a problem
to talk to the printer at times where ppi is currently not being used.
Another advantage is that inb()/outb() are restricted to the IA32
(aka. ix86) architecture, while ppi(4) is supported on any platform
with a parallel port (well, FreeBSD doesn't support that many
platforms right now).

Anyway, uisp doesn't seem to be maintained anymore.  Someone else here
in a German newsgroup told me that he's been doing a similar port for
Linux in the past (obviously Linux also offers some architecture-
independant parallel port driver now), but there seems to be no way to
exchange this modifications to other potential users of uisp.

My gripe with uisp was that there was no way to convince it to
actually talk to my chips where the chip ID has been erased.  I don't
know how this happens, but Atmel's application note AVR910 describes
this phenomenon: under some circumstances, it's possible that an AVR
chip doesn't repsond with the correct chip ID.  AVR910 talks about the
ID being 3 * 0xff, i've seen this, as well as 3 * 0x00 on one AVR 1200
chip.  The programmer i'm using now is able to override this, but uisp
never worked when i tried to hack the code to override the chip ID.

Oh, i'm seeing KG5LT.  Interestingly enough, my first `serious' AVR
project i'm thinking about will be a replacement for the
fixed-frequency crystal oscillators of old VHF walkie-talkies, to be
replaced by a DDS oscillator controlled by an AVR.  Hope i'll get it
working some day...

73 de DL8DTL
J"org Wunsch                                           Unix support engineer
address@hidden         http://www.interface-systems.de/~j

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