Verification error when using XBM images with a lot of black pixels

[oliverckhaas]

Hi all,

Wanted to share an issue that I encountered while working with the gratis sample sketches with the Repaper EPD development board hooked up to an Arduino UNO R3.

When uploading a custom XBM image in the demo2 sketch that contained a lot of black pixels, the IDE would throw the following error during the upload procedure and the display would render a corrupted image:

avrdude: verification error, first mismatch at byte 0x0080
         0xff != 0x00
avrdude: verification error; content mismatch

The reference image was an XBM at 264 x 176 px that contained only black pixels (5808 bytes of value 0xff). As expected, the error occurred when converting an XBM image in GIMP or generating it manually.

Our solution to this issue was a bit of a hack, but worked like a charm: we added 1px of padding to either side of the image canvas. These borders are, of course, barely noticeable to the naked eye.

Again, this is a hack, but it worked well for our project. If anyone has any more insight into the root of this issue or other suggestions for fixing it, please share below. It would be great to grow the body of knowledge around E Ink development boards.