SLRC400 Datasheet, PDF (18/130 Pages) NXP Semiconductors – I·CODE Reader IC

Philips Semiconductors
I•CODE Reader IC
Product Specification Rev. 2.0 November 2001
SL RC400
5.1.1 REGISTER BIT BEHAVIOUR
Bits and flags for different registers behave differently, depending on their functions. In principle bits with
same behaviour are grouped in common registers.
Abbreviation
r/w
dy
r
w
Behaviour
Description
read and
write
These bits can be written and read by the µ-Processor. Since they are used
only for control means, there content is not influenced by internal state
machines, e.g. the TimerReload-Register may be written and read by the µ-
Processor. It will also be read by internal state machines, but never changed by
them.
dynamic
These bits can be written and read by the µ-Processor. Nevertheless, they may
also be written automatically by internal state machines, e.g. the Command-
Register changes its value automatically after the execution of the actual
command.
These registers hold flags, which value is determined by internal states only,
read only e.g. the ErrorFlag-Register can not be written from external but shows internal
states.
These registers are used for control means only. They may be written by the µ-
write only
Processor but can not be read. Reading these registers returns an undefined
value, e.g. the TestAnaSelect-Register is used to determine the signal on pin
AUX, but it is not possible to read its content.
Table 5-2: Behaviour of Register Bits and its Designation
18
Preliminary