strophlex Posted November 7, 2008 Report Share Posted November 7, 2008 HiI just tried to set up my 4x20 oriental display on my mb6582 and get this uggly result. I have connected the display from my mb64 to the mb6582 and it looks good except that it is small. I have tripple checked the wireing and it is correct. I think the display is broken one way or the other, anybody has a better idea?Thanks. Quote Link to comment Share on other sites More sharing options...
cimo Posted November 7, 2008 Report Share Posted November 7, 2008 looks like cs are inverted Quote Link to comment Share on other sites More sharing options...
strophlex Posted November 7, 2008 Author Report Share Posted November 7, 2008 looks like cs are invertedInteresting, what does that mean and how can I fix it? Quote Link to comment Share on other sites More sharing options...
cimo Posted November 8, 2008 Report Share Posted November 8, 2008 i know thatI have tripple checked the wireing and it is correct.but have you got the right datasheet for the lcd ?what s the lcd model? Quote Link to comment Share on other sites More sharing options...
strophlex Posted November 8, 2008 Author Report Share Posted November 8, 2008 i know thatbut have you got the right datasheet for the lcd ?what s the lcd model?It is this one http://character-lcd-lcds.shopeio.com/inventory/details.asp?id=1287&cat=Lcds&sub=Character%20Lcd . Same as Kartoshka made a bulk order of some time ago. In the data sheet it looks like the connectors are the same as the example in the lcd module part of ucapps. So I think I have the right data sheet. Quote Link to comment Share on other sites More sharing options...
Wilba Posted November 8, 2008 Report Share Posted November 8, 2008 This model of display works fine when connected to a MIDIbox, in 8-bit and 4-bit mode (PIC18F4685 uses 4-bit by default).So if you used the default wiring (and I'm assuming you did), then it should work.There is nothing wrong with your wiring, because the display is almost showing the correct text for MB-SID...I can see what should be:E002|A001 Ld Chn. 11---|Lead Patch[/code]therefore the LCD is receiving the correct data - this is a character LCD, the PIC only sends characters (i.e. ASCII codes) so for the display to show incorrect/garbage characters means the problem is in the LCD. It looks like whole rows and columns of the display are not lit... they're blacker than a "black" LCD pixel. This is a negative display so pixels that are black/unlit should still have a bit of glow behind them, you can see this on the display, but then there are even darker lines... I don't know much about LCDs but that to me suggests the LCD material is faulty.I hope you can get a refund or replacement for it... :( Quote Link to comment Share on other sites More sharing options...
nebula Posted November 8, 2008 Report Share Posted November 8, 2008 ^^^ Agreed. Looks like a faulty LCD module.$25 is a lot to spend on an LCD with no commitment from the vendor. You should email them, and tell them you hooked another LCD up to your project and it worked fine. Chances are they will just send you another one, especially since you have a photo to show them. It is possible, but unlikely, that they will want the old one back. For them, it's not worth trying to fix. For you, it might be - if the vendor lets you keep it, look all over the module for any bad or bridged solder joints. Just make sure you get a commitment to have it replaced before you play around with it. I had the worst time with one LCD because I was messing around with the jumpers on the side (the little surface mount chip resistors). I put it back to its factory configuration and it no longer worked correctly. I needed a magnifying glass to see that I had left a very tiny dab of solder bridging two vias (the little metal grommets that connect one side to the other). It was almost impossible to see because they were less than 1 mm apart. Quote Link to comment Share on other sites More sharing options...
strophlex Posted November 9, 2008 Author Report Share Posted November 9, 2008 Thanks guys! I will try to get a new display from shopeio. Quote Link to comment Share on other sites More sharing options...
strophlex Posted November 19, 2008 Author Report Share Posted November 19, 2008 I soldered some 2x40 displays for my sequencer yesterday and ran in to an odd construction. In the datasheet it says pin 15 is A / B+ and 16 is K / B-. This gives me the impression 15 should be connected to B+ (connected to +5V) on the core. The problem is that when measuring in beep mode with the multmeter it is clear that pin 15 is connected to ground on the display. I tested this on a completly virgin display too, so that must be the construction. If I connect it this way around it result in a short cirquit. I tried before realizing this and got a really hot regulator :P.Anyway I got the display working without backlight with 15/16 disconnected.Who is stupid here, me or the manufacturer? I guess I am to stupid to realize I am stupid. There are connectors for A and C on the other side of the display. Can I use them to connect backlight volitage instead?Not a word from shopeio yet. Quote Link to comment Share on other sites More sharing options...
strophlex Posted November 21, 2008 Author Report Share Posted November 21, 2008 I got it working. Just ignored pin 15/16 and soldered the backlight power to A/C on the other end of the display. My only problem with the 2x40 displays now is that the text is weak. I turned the contrast pot up to max but it is still not sharp enough. I guess there is some voltage that could be raised a bit. Quote Link to comment Share on other sites More sharing options...
strophlex Posted November 21, 2008 Author Report Share Posted November 21, 2008 After measuring some voltages I realized I have to turn the contrast pot to get 0V to get any text on the lcd and I would like to get some negative voltage to get it good enough. In the data sheet a Vopr=Vdd-Vlc is defined and supposed to be around 5V so it makes sence that I have to turn Vlc to 0 to get it working. Getting a slightly higher Vdd would solve the problem I think, but I guess that would cause other problems instead. Quote Link to comment Share on other sites More sharing options...
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