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Resolved: Graphics Board won't display anything

Added by haiku about 1 year ago

Hi, I've been having a hard time getting my graphics board to display anything and I'm not sure what to try next. I thought I'd upload where I'm at here and hopefully someone can point me straight.

What I've done so far
I've followed the assembly instructions here (https://jeelabs.org/2010/11/16/assembling-the-graphics-board/) and I'm at the point where I should have the minimum set of parts soldered up to drive the display. The link to the 'glcd_demo.pde' seems to be dead but I found the 'glcd_demo.ino' code here (https://github.com/jcw/glcdlib/tree/master/examples/glcd_demo) which I'm assuming is the same?

// Demo display for the Graphics Boad
// 2010-11-14 <jc@wippler.nl> http://opensource.org/licenses/mit-license.php

#include <GLCD_ST7565.h>
#include <JeeLib.h>
#include <avr/pgmspace.h>
#include "utility/font_clR6x8.h"

GLCD_ST7565 glcd;

void setup () {
    rf12_initialize(1, RF12_868MHZ);
    rf12_sleep(RF12_SLEEP);

    glcd.begin();
    glcd.backLight(255);
    glcd.setFont(font_clR6x8);

    // draw a string at a location, use _p variant to reduce RAM use
    glcd.drawString_P(40,  0, PSTR("GLCDlib"));
    glcd.drawString_P(10, 16, PSTR("ST7565 128x64 GLCD"));
    glcd.drawString_P(22, 32, PSTR("Graphics Board"));
    glcd.drawString_P(20, 48, PSTR("JeeLabs.org/gb1"));

    glcd.drawCircle(5, 5, 5, WHITE);
    glcd.fillCircle(121, 5, 5, WHITE);
    glcd.fillCircle(6, 58, 5, WHITE);
    glcd.drawCircle(121, 58, 5, WHITE);

    glcd.drawLine(40, 9, 81, 9, WHITE);
    glcd.drawLine(40, 11, 81, 11, WHITE);
    glcd.drawLine(0, 42, 14, 28, WHITE);
    glcd.drawLine(112, 42, 126, 28, WHITE);
    glcd.drawRect(0, 28, 127, 15, WHITE);

    glcd.refresh();

    Sleepy::powerDown(); // power consumption is now only the GLCD + backlight
}

void loop () {}

I'm using a JeeNode V6 with a USB bub 3 to power it. After I upload this code though nothing displays at all. I tried connecting the backlight and that seems to work fine. In fact if I change 'glcd.backLight(255)' to 'glcd.backLight(0)' the backlight turns off like I'd expect (although values in between do not gradually turn on the backlight with a dimmed brightness as I expected) which tells me something is working. I also tried the LED demo for the JeeNode just to make sure that's working and that worked fine. I also tried changing it from WHITE to BLACK in case I was trying to display white on a white background but it made no difference.

Here are a few images of my set-up:

The display showing nothing with backlight on behind it
display showing nothing with backlight behind it

The components I've soldered to the board
compenents soldered to board

Alternate view
alternate view

Close up of the resistor
resistor close up

Any help would be appreciated, as I said I'm not sure what I should try from here. Only things I can think of is maybe I'm running an old version of the demo code. I doubt the display itself is broken, and I haven't removed any of the protective films from it so I couldn't of accidentally removed one of the polarising filters.

IMG_7149.JPG (2.66 MB) IMG_7149.JPG display showing nothing with backlight behind it
IMG_7150.JPG (3.19 MB) IMG_7150.JPG compenents soldered to board
IMG_7151.JPG (2.72 MB) IMG_7151.JPG alternate view
IMG_7152.JPG (2.89 MB) IMG_7152.JPG resistor close up
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Replies (39)

RE: Graphics Board wont display anything - Added by haiku 12 months ago

Just tried uninstalling the driver and re-installing from the latest win x64 driver from here (http://www.ftdichip.com/Drivers/VCP.htm), it didn't fix the issue though.
I also got a new cable but like you predicted it made no difference.

RE: Graphics Board wont display anything - Added by haiku 12 months ago

Ok, I just tried with another laptop that duels boots Win 8 with Ubuntu. Win 8 had me running into the same story as before but when I tried Ubuntu and looped the TX and RX pins, messages echoed in the serial monitor like they are supposed to. So yeah, looks like I am having a driver issue with Windows.

I'm going to try uploading code with the BUB 2 via Ubuntu and see if that gets the displays working and at the same time delve deeper into the world of Windows drivers and see if I can work out what's up.

Would the wrong drivers with the BUB 3 caused the glcd to not work?

RE: Graphics Board wont display anything - Added by haiku 12 months ago

Quick update - I just tried uploading the glcd_demo.ino (https://github.com/jcw/jeelib/blob/master/examples/Ports/glcd_demo/glcd_demo.ino) sketch with Ubuntu. The upload worked but the display is still blank.

RE: Graphics Board wont display anything - Added by martynj 12 months ago

Is C6 installed? (Sorry for the fuzz - taken in haste...)

RE: Graphics Board wont display anything - Added by haiku 12 months ago

Ah I was wondering what that extra capacitor was for. No its not but should it be? I didn't see any mention of it in the assembly instructions or in JohnO's photos of his board either.

RE: Graphics Board wont display anything - Added by martynj 12 months ago

Possibly a red herring - just trying to eliminate variations between a known working set up and what you have.
When driving from BUB III glcd.begin(0x05) gives a reasonable contrast.

RE: Graphics Board wont display anything - Added by haiku 12 months ago

I just soldered in C6 and changed the contrast to 0x05 for the BUB III, I'm back on the original laptop with windows right now but it doesn't look like it made a difference. I don't think its a contrast problem given when I plugged in the new display from the second GLCD into the first board it did display for a second or two and I could read it fine. Its just after that it behaved like the original display and never displayed again.

RE: Graphics Board wont display anything - Added by martynj 12 months ago

You are using standard 60/40 multicore solder for assembly? The display is a classic LCD mechanism - the multiple voltages between the layers are generated by charge pumps in the driver chip, hence the multiple capacitors for charge storage. This involves μA currents i.e. high impedance nodes as you saw when trying to measure the voltage on various pins (it needs a DVM with several MΩ input resistance to capture these accurately).
The bottom line is that there may be flux residue bridging across one or several of the storage caps, collapsing the generated stored charge.
A squirt of IPA cleaner and fine toothbrush may yield results.
Also if testing is done ahead of permanently soldering in the display, the legs need to be scrupulously clean to make a good contact. The top two groups of three are used only for location, not signals - it's the long row that is important. Symptoms of poor connection will be slight tilting of the display w.r.t. the motherboard causes misbehaviour.

RE: Graphics Board wont display anything - Added by haiku 12 months ago

The solder I'm using is this lead-free solder from maplin: https://www.maplin.co.uk/p/maplin-lead-free-solder-100g-n29ar

RE: Graphics Board wont display anything - Added by JohnO 12 months ago

Hi `@haiku,

Have you had time to clean your board with Isopropyl Alcohol (IPA)? I am keen to share in the root cause of these issues.

RE: Graphics Board wont display anything - Added by haiku 12 months ago

Hey JonnO, I haven't cleaned the board but I have got it to work and I'm pretty sure I know what the problem was.

As an update for anyone following this thread with similar problems, I ordered a tested pre-assembled unit from Digital Smarties since I have a deadline with this particular project and I was running out of time to spend debugging everything I could have done wrong. Props to Martyn for sorting me out with what I needed.

Basically there were two issues. The first is that my displays weren't fully inserting into the header. Compared to the working unit they sit about maybe 3mm higher in the header and with screen 1 nothing I do will physically get it to slot into the header any further. At the time I just assumed that was how it was supposed to be but now that I do know they should go lower I retried screen 2 and found sometimes I am able to push down one half of the display a little bit further so that its wonky but it gets it to work. I'm guessing when I first tried screen 2 I must have had it barely in the header so that it worked at first and as I handled it it lost connection. Since most of the debugging after that was with screen 1 I never guess I never quite inserted screen 2 in the right way again. I think the problem might be some solder on one of the header pins flowed up and is partially blocking it, making it so the displays won't slot in fully. Since the pins are not completely straight on each display it just happens one display is able to slot in a little further than the other.

When I tried both my screens in the working unit I found only screen 2 worked. I'm guessing at some point I really did kill screen 1, maybe I inserted the board the wrong way round one time when trying to get it to work without realising. I also found they were much harder to slot in (maybe because as I have used them the pins have become less uniform?) but they do slot in further in the end.

I said the problem would be something stupid like that :), looks like I just needed to plug it in.

RE: Graphics Board wont display anything - Added by jcw 12 months ago

Aha, that clears things up! - I kept quiet because I just couldn't think of anything useful to say or help.
It would be good to have a good sideways photo shot of how far it should be pushed in to work properly.
And yes, glass with circuits & pins on them is a bit brittle. There is a limit to how much pressure it can take.

RE: Graphics Board wont display anything - Added by haiku 11 months ago

Here are some images from the side.

This shows display 2 not inserted enough to work, this is the maximum distance I could ever get display 1 go without risking applying too much pressure. Before I saw display 3 I just assumed this was how it was supposed to be.
display 2 not working

This is display 2 working as one side is pushed slightly further in. It took me about 5 minutes of inserting and re-inserting to get it back in this position again and I'm pretty sure it would break if I tried to force it any further.
display 2 working

And finally display 3 inserted fully into the header. This one just slides in with ease like it wants to be there.

Display 3 - correct seating
It's really strange, I compared the pins on the two displays and if anything display 2 has the straighter pins, no way to know what's blocking it without being able to see inside the header. ¯|_(ツ)_|¯

display_2_not_working.png (4.45 MB) display_2_not_working.png display 2 not working
display_2_working.png (4.2 MB) display_2_working.png display 2 working
GLCD_pin_depth.jpg (87.1 KB) GLCD_pin_depth.jpg Display 3 - correct seating
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RE: Graphics Board wont display anything - Added by JohnO 11 months ago

The connector on display 2 is not flush to the board and appears to have generous lumps of solder between the board and the connector. I wonder if the connector holes are blocked with solder. You could remove the connector and add a new one with less solder perhaps.

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