(don't know if this happens with host-supplied data)
-watchdog should disable CDU
-
-
-residual stuff from CDU is present and changes pt0 when you
- * turn on
- * say `+' to master to turn on CDU
- * switch to programming mode
- pt0 on pic2 is the one nearest the switch box, moving to hacker's right
- (we think - I haven't checked this yet)
-
-
layout polarity diagram colourful segment encoding:
make moveable feature selection in subseg2display bitwise rather than
setwise