It's far too simple to be true.

The e-paper I obtained included a connection diagram and sample software to get it running.

It looked straightforward but being the skeptic that I am it seemed too simple to be true.

My inital hunch was spot on.

I followed the instructions to the letter and there wasn't enough material to get it working.

Some additional research was required.

The Connector

The first thing I noticed was that of my previous blog. The connector on the e-paper interface connector was incorrect.

Even with this now correctly resolved ....

   Nothing.

The Code

The published code sample had an IAR Workbench sample.

This had to be decoded to work out where it needed to be located in order to be compiled correctly.

The correct path is C:\Users\<xxx>\AppData\Roaming\energymicro\kits\EFM32GG_STK3700\examples\EPD Extension Board v0.92 for EMGG\iar

(Substitute <xxx> with the user name directory name for your installation)

This is not dissimilar to the standard STK3700 examples.

Even with the correct location used and successful compilation ....

   Nothing.

The Necessary Adjustments

Since the above did not work it was now time for some debugging.

Working on the premise that the published connection details and code were correct and that I had connected it up correctly (A very dangerous premise indeed!);

I looked in the example code for program code constants that related to the model of e-paper that was connected.

Sure enough there was. The default model was not the same as the one I was using so I adjusted the values.

(I was using a 2.70 inch model. The default was the 4.41 inch model. - The funny thing about this was that the 4.41 inch hasn't been released yet.)

There is a constant used to define the display model number and a constant used for its corresponding example image.

ImageData.h    

     #define USE_EPDType DisplayEPD270

main.c

     EPD_DisplayFormPtr(EPD_270,(uint8_t *)&Image_2_70_1);

Now with these adjustments in place ....

    The code was rebuilt and downloaded and the display worked instantly.

Here's a picture of the successful result showing the non volatility of the e-paper display.