Pulse Width Modulation idle brightness

The lowest value for setLCDBrightness is 0.002

int b = (int)(v*256 + 0.5);

gives 1.

There is a lot of flicker when idle because irregular frametimes due to peripheral poll. HR + accel.

Bangle.setPollInterval(4000);

default is 80ms.
But 4000ms seems to make the flicker much less severe. If you are not using HR/accel, it might come in handy.