NXP Semiconductors
P89LPC9321
8-bit microcontroller with accelerated two-clock 80C51 core
7. Functional description
Remark: Please refer to the P89LPC9321 User manual for a more detailed functional
description.
7.1 Special function registers
Remark: SFR 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.
P89LPC9321_1
Product data sheet
Rev. 01 — 9 December 2008
© NXP B.V. 2008. All rights reserved.
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