Missing line & rubbish characters, with 2x16 VFD

asterler · Post by **asterler** » July 29th, 2007, 8:34 pm

Hi Guys

I've got my first vfd, last Wednesday in combination with a Ahanix MCE302 htpc-case. This is a HD44780-compatible 2x16 vdf.
When I start up smartie, the vdf works, but eventually (after minutes or hours) it will only show the top half screen, sometimes with the right characters, sometimes with rubbish characters, like: ##F||!!VV#fff|| (Usually wired signs, and f's and v's). The program is still sending data to the vfd, as the rubbish changes along with the scroll interval.

If I restart smartie the vfd works again.

Here is what I've done so far:

I've tried using the HD44780.dll-driver and the FutabaVFD_LCD.dll-driver.
I've tried all the different LPT-modes in the bios (ECP,EPP,Normal and Bi-directional). Only EPP and Bi-directional works, and they're giving me the same problems.
I've tried different refresh intervals.
I've tried every possible combination of alternative adressing, boot delay, backlight setting and port(LPT/$378).
I've tried both version 5.3 and 5.4.
I've installed the "linx port i/o driver"

What is (probably) not the cause:

Some other program interfering with the parallel port? (I can't imagine what program. Never used the parallel port with other software.)
Wrong connection/bad cable/bad vdf? (If restarting smartie solves the problem, I think it's a software problem)

I need some help here...

EDIT:

Here is a picture of the VFD with rubbish characters
http://image.bayimg.com/aaeccaabo.jpg

outofspace · Post by **outofspace** » July 30th, 2007, 12:49 pm

I'm having exactly the same problem.

I've tweaked and tweaked the Timing multiplier even trying as high as 200 but hasn't made any difference.

Each time after a few minutes I get the garbage as above.

asterler · Post by **asterler** » July 30th, 2007, 3:37 pm

I think the problem is that the display can't keep up with all the data smartie is sending, and eventually it will loose some packets and then start reading the data wrongly (understand me?), and thereby show garbage.

I've been up all night, keep on tweeking and maybe found a solution. The display has now been correct for about 10 hours.

Here is what I've done, you could try this as well:

All of my previous testing has been done on my winamp screen with a scrooling title, a visualizer(using winamp.dll) and time/remaining time. Because of the visualizer the refresh interval couldn't be more than ~60 ms. (>60 ms. -> ugly visualization), so I removed the visualizer, and set the refresh and scroll interval to 200 ms. Maybe it's just a coincidence, but I also think that lowering the backlight would make the lcd more stable. So you have to use the FutabaVFD_LCD.dll-driver to try this. Mine is set at about postion 2, if 1 is completely left and 5 is completely right (understand me?). Same position with the contrast, eventhough this properply doesn't matter. The port command is LPT1,5,0,0 (Multiplier 5, and no 1x16 adressing).

asterler · Post by **asterler** » July 30th, 2007, 4:44 pm

Well I decided to take out my display, and check the connections (according to http://sourceforge.net/forum/forum.php? ... _id=416971)

Then a looked at my vfd. It's looks like melted or something in one end.

Two pictures:
http://image.bayimg.com/kaemaaabo.jpg
http://image.bayimg.com/maemlaabo.jpg

Does anyone know if this is how it should look, or maybe what could have caused this?

Post by **mattcro** » July 30th, 2007, 9:05 pm

The silvery blobs inside the VFD are perfectly normal. Those deposits are the remains of gases present inside the tube when it's being assembled. A special process deposits any remaining gases onto the "getter", as it's called, and the result is a (near)perfect vacuum in the tube.

What sort of cable are you using to connect to the PC? Sometimes the length and type can have an effect. How are you powering the VFD?

asterler · Post by **asterler** » July 30th, 2007, 9:51 pm

It's a Soundgraph/Imon vfd used by many of the htpc case manufacturers. The vfd came factory assembled (vdf+molex connector+parallel cable) with my case (Ahanix MCE302). Molex-connector to psu and parallel cable to parallel port. I tried checking the wiring with a multimeter, but I couldn't find any wrong connections.

Maybe I will try making my own parallel cable, for the vfd, but I'm not sure if its worth the effort. I have to find a cable, solder etc., and it would properly make no difference.

The usb-version (incl. a IR-reciever, and new vfd) is available for about 300 dkr. (~55$). Does anybody know if this Imon vfd with usb-connection, is compatible with lcd smartie?

Post by **mattcro** » July 31st, 2007, 5:51 pm

The VFD wiring should be fine since it's a pre-assembled one - you'd expect them to know what they're doing! The possibilities for corrupt display are then something interfering with parallel port comms (windows trying to find a printer?), hardware issues (port settings maybe) or (really not sure about this, never been a problem for me) the possibility that Smartie does occasionally produce corrupt output.

I'm not sure about the USB iMON display - I think it'll work since Smartie uses the iMON software/driver to access the display.

I suppose that's how the parallel port version is supposed to work too. Have you tried that? Set Smartie to use the imon.dll display plugin, and set the iMON software to 3rd-party plugin mode or something (I'm not sure of the details).

asterler · Post by **asterler** » July 31st, 2007, 7:53 pm

Thanks for the tips mattcro. I've tried what you've suggested + some other new things.

The case actually comes with Smartie+drivers as the software for the display. It's Smartie 5.0, but 5.3/5.4, as I'm using now, should work as well, right?

I've tried what you wrote about smartie & iMON together (using the 3rd-party mode and imon.dll), but smartie shows an error (Some thing like .. "Can't find display"). Maybe it's looking for a usb-connected display? I have pointed to the right sg_vfd.dll-path in the command field. imond.ddl doesn't work either.

The parallel port is set to EPP mode as suggested on Ahanix' website (http://ahanix.com/support/faq.php?id=24). I've also tried other modes without succes as stated in my first post.

I'm using a 1? week old install of xp, and nothing except the display, has ever been connected to the parallel port. Therefore I can't think of any other program exept Smartie (and Windows itself ) that tries connect to the parallel port. I've tried what you wrote about the checkbox in the parallel prot properties called "Search for plug and play devices" (I'm not using an English Xp-version, but it's something like that in English). I've tried both disabling and enabling it without succes. I've also tried the different modes of interrupt modes you can set at the top. No difference.

I have a volume screen (activated by changing volume) with a volume bar in the bottom line, which scroll along with the volume change. When the display shows garbage on in the top line, and I change the volume (thereby change to the volume screen), I can see some of the rubbish, kind of scroll along with my volume change (get the image?). This must be because some of the data to the bottom line is placed in the top line. I think the display only gets hold of some of the data or maybe read the data wrongly.
I'm not into how the vfd-parallel connections works, but I have thought a bit about it, and here is what I think is wrong.
If the data for the top line is called (T) and the data for the bottom line is called (B) an image of the data sent from the smartie to the vfd could be like this:

But if the display reads the data is a little too late, the data could be read like:

Which would make the vfd try to display BB (garbage!) instead of TTTBBB. The garbage would be placed in the top line and nothing in the bottom line.

This could explain why I have nothing on the bottom line, but garbage on the top line. And this could also be the reason why the garbage data, scrolls when the volume is changed.

Is this a possible scenario

And if it is, is there a solution?

outofspace · Post by **outofspace** » August 21st, 2007, 6:58 pm

I have the same case.

Whats interesting is that LCD Smartie worked before I upgraded and I only started to get the garbage after changing my hardware.
(Fresh XP Install BTW)

Apart from the multiplier is there anyway of slowing the communication down?

LCD Smartie always starts fine its just after a while I get garbage?

And I tried JaLCD and get the garbage too, this must be a parallel driver issue or something like that.

My motherboard is a Gigabyte GA7-NNXP (NForce 2 chipset)

asterler · Post by **asterler** » August 21st, 2007, 9:17 pm

I never found a way to make the parallel VFD work. I bought the usb-version, and it has worked ever since...

outofspace · Post by **outofspace** » August 22nd, 2007, 7:53 am

Could you give me the link to the site where you got your USB one from please?

Cheers

asterler · Post by **asterler** » August 22nd, 2007, 12:25 pm

Here is the link:

http://www.getmore.dk/templates/imw-pro ... +VFD+Black

It's a SoundGraph IMON VFD. There's a lot of shops which sells these. The price here in Denmark is 322 kr. (shipping incl.) (~55 $). It also includes a nice remote. After some tweaking I also got this to work, while Smartie was still controlling the VFD. You should be able to google a shop shipping to your country....