Philips Semiconductors

Product specification

89C51/89C52/89C54/89C58

80C51 8-bit microcontroller family

4K/8K/16K/32K Flash

1999 Oct 27

27

Security

The security feature protects against software piracy and prevents

the contents of the FLASH from being read. The Security Lock bits

are located in FLASH. The 89C51/89C52/89C54/89C58 has 3

programmable security lock bits that will provide different levels of

protection for the on-chip code and data (see Table 8). Unlike the

ROM and OTP versions, the security lock bits are independent. LB3

includes the security protection of LB1.

Table 8.

PROTECTION DESCRIPTION

Level

PROTECTION DESCRIPTION

LB1

MOVC instructions executed from external program memory are disabled from fetching code bytes from

internal memory.

LB2

Program verification is disabled

LB3

External execution is disabled.

NOTE:

1. The security lock bits are independent.