89C51 Philips Semiconductors, 89C51 Datasheet - Page 27

• Manufacturer Part Number: 89C51
• Description: 80C51 8-bit microcontroller family 4K/8K/16K/32K Flash
• Manufacturer: Philips Semiconductors

1. The security lock bits are independent.
Philips Semiconductors
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.
NOTE:
1999 Oct 27
80C51 8-bit microcontroller family
4K/8K/16K/32K Flash
SECURITY LOCK BITS
Level
LB1
LB2
LB3
1
MOVC instructions executed from external program memory are disabled from fetching code bytes from
internal memory.
Program verification is disabled
External execution is disabled.
27
PROTECTION DESCRIPTION
PROTECTION DESCRIPTION
89C51/89C52/89C54/89C58
Product specification