Since I had to compile owfs from sources anyway, I can easily test code changes
and
patches regarding this topic. But as I am not an expert with big C/C++ projects
I
would need some support here.
I had a look at ow_2408.c in which I found FS_Mscreen and FS_Hscreen (which uses
OW_Hprintyx). As I am not very familiar with those piece of codes I wanted to
ask
what is the most simple way to switch the upper and lower nibble of the byte
applied
to the switches (P0..P7)?
Thanks in advance and greetings
Ursin Solèr
Solèr Ursin; Mon, 31 Aug 2015 09:11:33 -0700
> Dear OWFS Developpers
>
> First I'm using OWFS for several months now and are generally very satisfied
> by
> this nice and useful software - nice job and please carry on! :)
> The reason why I write this is in summary that I am confused by the LCD
> control
> situation as given by [1] and [2]. Exactly speaking the Maxim and
> AagElectronica
> designs.
>
> [1] http://owfs.org/index.php?page=lcd
> [2]
http://sourceforge.net/p/owfs/mailman/owfs-developers/thread/45BE3E8F.4040905%40proquariat.de/#msg10970280
>
> I was looking for a supplier (here in Switzerland) for any 1wire LCD. I was
> able to
> get a Louis Swart and a LCD Display 163 [3]. Could not find any supplier for
> other
> LCD devices - since they are either obsolete, the company does not sell to my
> region or does not exist anymore.
>
> [3]
http://www.eservice-online.de/media/pdf/Bedienungsanleitung%20LCD%20Display%20163.pdf
> (in German)
>
> The issue now is; if I look at the Maxim "4bit design" in [2] (see [4]) and
> compare it
> to the AagElectronica in [1] and to the EService one [3] (pin assignment table
> on
> page 3) they are all the same with respect to the LCD control lines (P0-P4).
> And
> according to [1] are "Supported as 29.x/LCD_M/".
>
> [4] http://datasheets.maxim-ic.com/en/ds/DS2408.pdf
>
> However this does not work (tested it) and must somehow be wrong considering
> again
> [1] and the given "Maxim" design schematic [5] "Supported as
> 29.x/LCD_M/"
> as well as the Maxim "8bit design" mentioned in [2] and [6]. As mentioned in
> [6] the
> Maxim design (LCD_M) must be the 8bit one and is thus NOT the AagElectronica
> design!
> This fits with my observations since the EService LCD switches background
> light
> which
> is controlled by the other pins, when trying to write text.
>
> [5] http://www.maxim-ic.com/images/appnotes/3286/3286Fig01.pdf
> [6] http://sourceforge.net/p/owfs/mailman/message/10209248/
>
> So from what I can see the Maxim "Reference" Design "Figure 18. DS2408 AS
> SLAVE
> INTERFACE FOR INTELLIGENT DISPLAY" mentioned in [4] page 29 is not implemented
> in OWFS yet, correct? I would like to request to implement this feature. May
> be
> easiest
> way is to derive from HobbyBoards since this is know to work with 4bits [7]
> (upper
> instead of the lower nibble). May be just have a switch to configure which one
> to use...
>
> [7] http://sourceforge.net/p/owfs/mailman/message/31840734/
>
> I am willing to help coding and testing, if someone familiar with the code
> could guide me.
>
> Thanks a lot and Greetings
> Ursin Solèr
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