© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
User manual Rev. 02 — 23 May 2005 13 of 133
Philips Semiconductors UM10109
P89LPC932A1 User manual
1.4 Special function registers
Remark: Special Function Registers (SFRs) accesses are restricted in the following ways:
•User must not attempt to access any SFR locations not defined.
•Accesses to any defined SFR locations must be strictly for the functions for the SFRs.
•SFR bits labeled ‘-’, ‘0’ or ‘1’ can only be written and read as follows:
–‘-’ Unless otherwise specified, must be written with ‘0’, but can return any value
when read (even if it was written with ‘0’). It is a reserved bit and may be used in
future derivatives.
–‘0’ must be written with ‘0’, and will return a ‘0’ when read.
–‘1’ must be written with ‘1’, and will return a ‘1’ when read.