MC68HC11KW1 Datasheet, PDF (4/238 Pages) Motorola, Inc – High-density complementary metal oxide semiconductor HCMOS) microcontroller unit

Conventions
Where abbreviations are used in the text, an explanation can be found in the
glossary, at the back of this manual. Register and bit mnemonics are defined in the
paragraphs describing them.
An overbar is used to designate an active-low signal, eg: RESET.
Because the bits in any one register are not necessarily linked by a common
function, the description of a register may appear in several sections referring to
different aspects of device operation. A full description of a bit is given only in a
section in which it has relevance. Elsewhere, it appears shaded in the register
diagram and is only briefly described.
When the state of a bit on reset is described as ‘x’, this means that its state depends
on factors such as the operating mode selected. A ‘u’ indicates that the bit’s state on
reset is undefined.