Review week 15: device checks

This week was about not addressing devices blindly. The key points for review:

• ReferenceId: every device number is fixed. You read it with l r0 d0 ReferenceId, after that l r1 r0 Temperature works with the number in the register.
• sdse / sdns / bdse / bdns: first ask whether a device is there, then read.
• bdnvl / bdnvs: jump when a device cannot read or cannot write a LogicType.
• dr0: the pin whose number is in r0 – ideal for loops over all pins.
• Deprecated: ld, sd, getd, putd and label still run but no longer belong in new code. l, s, get and put take the ReferenceId themselves.

You pass from 60 %, the explanations appear after handing in.