12C Backpack Alternate Wiring

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mattbrailsford
 
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Joined: Tue Nov 22, 2011 12:22 pm

12C Backpack Alternate Wiring

Post by mattbrailsford »

Hi Guys,

Just got my I2C backpack + Bi-color 8z8 matrix today and have been wiring it up. Now, I have a specific use in mind for this which has led me to wire it a bit differently. Instead of soldering the screen on the back side, I have used female headers and mounted the screen above the chip (I figure this just reverses the order of the pins).

This kinda works, but the rendering isn't quite as "backwards" as I was expecting. Rather than the whole image just being backwards, it's actually split into 4 segments that render correctly, just in the wrong order (see attached example of the smily example program, you can see the 4 (4x4) corner segments are right, just in the wrong order).

Can anyone suggest what changes to the LEDBackback library I need to "shift" it? (I'm assuming something in writeDisplay()).

Matt
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mattbrailsford
 
Posts: 22
Joined: Tue Nov 22, 2011 12:22 pm

Re: 12C Backpack Alternate Wiring

Post by mattbrailsford »

After a couple of hours tinkering, I found it :)

I actually updated the drawPixel method and added the following before the color if statements:

Code: Select all

  if(x < 4){
    x += 4;
  } else {
    x -= 4;
  }

  if(y < 4){
    y += 4;
  } else {
    y -= 4;
  }
Matt

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