Anelok: battery, display errors, evolution update

Werner Almesberger werner at
Mon Feb 23 09:47:41 UTC 2015

Assorted items:

- not to belittle the pure joy and excitement of watching paint dry,
  but monitoring a battery's epic journey towards inevitable doom is
  so much more rewarding:

  So last week's drop was caused by the cold weather, not the battery
  showing first signs of weakness. Now that summerly temperatures are
  back, so is the battery voltage. To be continued ...

- then there is an ugly truth I hadn't revealed yet: sometimes, the
  display of Anelok would look like this:

  I thought that this may have been caused by timing issues in the
  communication between MCU and OLED, but I was a little worried by
  me already having verified the timing some time ago without
  finding any problem - which would then suggest a more fundamental

  Well, while playing with the slider, I noticed that this sort of
  pattern would reproducibly occur at the same positions when
  scrolling. As we know, if you can reproduce it, you can fix it.
  So I did ...

  It turned out to be a missing sanity check in my bit blit
  function, which allowed it to attempt to draw things that were
  completely off-screen. With that fixed, I haven't seen any more
  such corruptions, and I sleep a lot better now :)

  Note that this is different from the signal integrity issues
  caused by voltage mismatch between MCU and OLED. That still needs
  solving, but it's pretty clear what's happening there.

- I've updated the hardware evolution diagram:

  The previous version (April 2014, how time flies) is here:

  The differences:

  - CPU: added the "dual processor" (KL16+KL26) combo as future
    development possibility.

  - USB device: added using a Micro B receptacle (instead of Micro AB)
    as something to consider.

  - slider: while a bit more tuning will be needed, it looks good enough
    nowadays that I think we can safely bury the wheel.

  - RF-kill: the brute simplicity of shorting RF VDD to ground shall be
    the way to go.

  So this leaves testing operation on CR2032 as the last major open

- meanwhile, Xiangfu sent these pictures:

  The second one shows that the capacitive slider now works on these
  boards, too.

- Werner

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