MB6582 - rc30 - LCD issue

[dioioib]

So I am having some issues with the Optrex screen I purchased a while back, I did have it working for a short period a few months back. But, I placed the project on hold and upon returning to it, the connectivity seems to be broken.

I have reinstalled the .hex file using MIOS studio. - no effect

I have rewired the LCD screen -no effect

tried a different LCD 16x2 with a modified .hex file and do not get the same problems but I still don't get output on the screen. But I do get a backlight with this one.

My powersupply is 1.0A @ +5v and 0.75A @ +12v.

Screen is:

http://www.optrex.com/products/partdetail.asp?PartNumber=C-51847NFJ-SLW-ADN

and a video of the problem can be seen here:

http://www.viddler.com/explore/dioioib/videos/10/

thanks,

[Narwhal]

I'd place a bet on the wiring to the LCD.  Perhaps some detailed pictures of the LCD and the cable plugged into the main board could help get a second set of eyes to verify.  Miswired LCD's look have symptoms a lot like what your video shows.    I do the same thing all the time myself.

[dioioib]

Ok here are some additional photos

Showing alternate connections for Backlight, nothing is actually connected to this.

http://www.bdis.ca/~briandurocher/public/midibox_errors/dioioib_3mb6582_lcd_000001060309.jpg

Header on the board.

http://www.bdis.ca/~briandurocher/public/midibox_errors/dioioib_3mb6582_lcd_000002060309.jpg

This is the connection to the 16pin's on the LCD. The 15 & 16th pins have been disconnected at this time as I was testing a suggestion listed on the wiki about improper backlight wiring  causing issues.

http://www.bdis.ca/~briandurocher/public/midibox_errors/dioioib_3mb6582_lcd_000003060309.jpg

Let me know what you think. I followed the pin / wire diagram tutorial from the wiki and matched that to the datasheet which is almost a 1:1 match.

[Wilba]

Can you try connecting this LCD to a different Core (on the MB-6582) with same PIC, and same Core with a different PIC?

This will help prove your problem is specific to the LCD or cable, or specific to the Core J15, or specific to the PIC.

Explain more about how your other 16x2 LCD "[does] not get the same problems but I still don't get output on the screen." If you know this LCD works, try it on other Cores on the MB-6582.

[Narwhal]

Can I get a picture of your third image from the other side, where I can see the wire colors and the pads they go to?  ie: Keep the LCD facing down, but just spin it around 180 degrees and take a picture.

[stryd_one]

Hmmmm, the 'black blocks' initialisation doesn't seem right, what's with all the missing blocks? Is that normal for that LCD? ... Doesn't look good :( (Perhaps a dead LCD...)

[Narwhal]

Your wiring looks correct.

<second eyes deactivate>

[dioioib]

Wilba:  the 16x2 LCD is displaying nothing on screen at all but the back light is driven by the mb6582.

to answer the question will this LCD work on other cores, no it does not its the exact same output, on all other cores.

I can not confirm if the screen works on any other devices as I have nothing to connect it too other than the mb6582.

I will try wiring another LCD tonight to see if this one is just burnt out. Lets hope not.

[Wilba]

Sorry but you are not being specific enough, I don't know if you are referring to the 16x2 or the 20x4

20x4 LCD, Core 1, PIC #0

20x4 LCD, Core 2, PIC #0

20x4 LCD, Core 1, PIC #1

20x4 LCD, Core 2, PIC #1

16x2 LCD, Core 1, PIC #0

16x2 LCD, Core 2, PIC #0

16x2 LCD, Core 1, PIC #1

16x2 LCD, Core 2, PIC #1

Describe the output in each case.

If none of these tests show a working LCD, then the problem is either

a) firmware uploaded with "LCD doesn't work" feature (most unlikely, you said it worked once)

b) multiple solder joint problems on more than one Core (unlikely)

c) bad LCD cable on more than one LCD (unlikely)

d) two busted LCDs (least unlikely)

You see how it's all unlikely? Very strange. So you need to be very precise what combinations you tested and what the results are, or we're all fumbling in the dark with wild guesses.

[Wilba]

P.S. Those tactile switches you use look different and interesting, can you post a closeup photo and maybe link to where you got them, datasheet etc?

[dioioib]

Well the 16x2 is not a screen I even intended on using with the mb6582, I just wanted to hook it up using a modified version of the mb6582.asm to see output. All tests and comments are directed toward establishing a connection with a 20x4 LCD.

The output in the video and pictures is the same for 20x4 LCD connected to J15 on core1, core2, core3 and core4. Firmware is version midibox_sid_v2_0_rc30 setup_mb6582.hex unedited.

I followed the info Wilba wrote in this thread:

http://www.midibox.org/forum/index.php/topic,12955.0.html

Currently wiring a new LCD. Will test ASAP.

[dioioib]

With the new screen the backlight stays on for a little while during the first power on however after which it will not come back on. This time there is nothing on the screen at all.

[dioioib]

ok so the screen works now. I used the HEX to Syx converter tool, and uploaded the data using SyxLibrarian for Mac.

The backlight on the unit is not working could this have been burnt out during the initial power up?

[Wilba]

Can you upload the datasheet for this Optrex LCD?

It's white LED backlight, sometimes (a lot of the time) these are edge-lit and use only a few LEDs, not a whole array. Thus they only need 25mA-40mA current and not 280mA+ like a typical yellow-green LED array LCD. It's possible you burned out the white LEDs.

If you want to use a low-power LED backlight, you need to add a resistor in series with R4 so that the current is limited. A good safe value is 47K, which will limit current to approx. 25mA or less.

[dioioib]

Sure thing the max mA is 60 and a recommended mA of 30.

I am going to rip the 2 lcd's appart and put new LEDs in them. there are only 2 and the display is very easy to take apart. The leds are right angle SMD and look like 0805's.

[dioioib]

as per request here is a photo of the tac-switches I used in my box.

http://www.bdis.ca/~briandurocher/public/midibox_errors/parts_mb6582_000004060409.jpg

I believe I sourced the part from Mouser but I am unsure as to what the part number is. I'll attempt to track down the invoice.