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Display Connection with Mirrored Pinout


novski
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I tryed to make a Board for the SCS. Actually a simple thing, but i got a strange failure i can't locate.

 

I drawn a Schematic with Eagle witch Simply connects the Display to a Pinheader - 1:1. But now i noticed that the Connections at the Core to my Board are Mirrored. So Pin 1 has 5V and Pin 2 GND.

I then Made single Connectors to the Connection J15A and Crossed every pin from upper row to lower and vice versa. That way the display runs, but still has some weird scrambled characters.

So i Connected my already running 2x16 OLED and rebooted. As you can see in the Attachment there it shows the full words correctly. 

I checked every pin twice and just can't understand that problem.

 

Edited a more clear Photographic of the 2 connections.

 

Thanks for any help...

post-10711-0-03872000-1361355054_thumb.j

post-10711-0-22816900-1361355063_thumb.j

post-10711-0-12844500-1361355083_thumb.j

post-10711-0-10835500-1361355150_thumb.j

post-10711-0-10694400-1361355247_thumb.j

post-10711-0-32843900-1361355854_thumb.j

Edited by novski
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That's a relatively simple error: when you designed the board, one of the connectors was supposed to be on a different layer than it ended up when you soldered it - either top or bottom. It's not clear to me from the images you provide, but maybe the LCD "component" that you apparently use expects the connector to be mounted on top, whereas you have it soldered to its bottom.

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Well i tried to consider that. but i think thats not my problem. If i draw a Schematic with Pin#1 conected to Pin#1 on the Header it shold always connect it the right way arround. I then checked the positions of the Headers and found them to be right. The header is on the Bottom side (mirrored in the properties). The Display on Top.

Is it possible that the Pinheader on the Core Board is wrong? (i have the Core PCB from midibox-shop.com)

if you look at the Scan i made befor i soldered it you can see that the Pin 1 of J15A is not identical with the Pin 1 on J8/9.

post-10711-0-40535700-1361378408_thumb.j

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Yes, that is the case, but it's only the little "1" that is wrong - if the notch of the "Wannenstecker" is pointing towards you, then pin 1 is on the left close to you. However, you could align the "1" marked on the board only properly to your cable's "1" if you had mounted it from below... which you probably haven't done anyways, right? So that marking alone can hardly be the sole cause for this :-/.

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The "Wannenstecker" is mounted to the Top. The last picture of my first post shows it... i can't follow...

 

Yes, that just shows that you got the cable / Wannenstecker on the LPC17 right, in spite of the misleading "1" marking. I was suspecting that there must be some other cause for you mixing up the cabling, and this confirms it, because on the LPC17 board you got it right... :smile:

 

My guess is that the problem is somehow related to the LCD component that you used in Eagle - I assume that this is what you used, it's a little hard to see because the second image in your first post is cropped.

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Well then that wold mean that the Display is supposed to be Connected on the Top side.

I can't understand that, because with a hight of 4mm the Connector will always block the mounting to a frontplate... 

 

At least this is what the data sheet suggests, and my displays have the same pinout.

 

One of your pictures (the Eagle PCB screenshot) looks as if you used a component that represents an LCD - at least it seems to print some silkscreen on to the PCB. That might be the cause for your confusion. I would suggest to use a simple Wannenstecker compontent, which you can then place on the top or bottom layer without being overly confused by the silkscreen. After having the PCB fabricated, mounting it either on top or on the bottom will then give you the correct pinout.

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