Re: [lcd4linux] 3x HD44780 problem / special character problem

[Michael R. <re...@eu...>]

Hi Kamil,


>> all three displays should share the RS line!

> Yes, they should, but since it is a 40x4 and therefore it has two=20
> controllers on one board I presume they share the RS line anyways.
> There is no second RS pin on the connection bracket.

You're right, I missed that point.

> Stefan ( geronet ) already picked up the issue but he has no further
> advice other than to look what's happening with an osci. While I have
> a 60MHz osci ( which should be sufficient ) I am not that familiar
> with the protocol and timings so I don't really know what to look
> for. Any advice here ?
No, not at the moment. I'd say we should investigate other things
beforehand.

Have you tried if the 20x4 display works standalone (i.e. without the 40x=
4)?

> Right, that's what I figured. Since it is a 40x4 lines 1&3 are filled
> with blocks. That issue got solved once I bought a new 20x4. Both
> Display initialize correctly now, but th 20x4 only shows garbage and
> the lines 5-8 which are supposed to be shown on the 20x4 are shown on
> line 1-4 above the original 1-4 definituin. I have taken pictures but
> I was hesitant to post into the ML because of traffic issues.
You can send me the pictures with PM.

So the problem is that not only the 20x4 is not working, but disturbs
the 40x4? Strange... Maybe there's a bug in the multi-controller code?

I' recommend trying if both displays work standalone.

1. disconnect the 20x4 completely, but don't modify the config file, and
look if you still get lines5-8 displayed on the 20x4.

2. disconnect the 40x4, and connect the 20x4 only. look what happens.
try to connect the enable line of the 20x4 to all three enable outputs,
so you should see different parts of your layout, but no garbage.

Maybe it's alectrical problem, the two displays produce too much load on
the parport...

> However, when the Display shows garbage he flicks some weird ASCII=20
> characters through it and I could clearly identify the =B0 sometimes.
> So I *guess* the Display is able to produce it when properly
> triggered.

Could you please send me your config file?


bye, Michael

--=20
Michael Reinelt <re...@eu...>
http://home.pages.at/reinelt
GPG-Key 0xDF13BA50
ICQ #288386781