P89C668 Philips Semiconductors, P89C668 Datasheet - Page 51

• Manufacturer Part Number: P89C668
• Description: 80C51 8-bit Flash microcontroller family 64KB ISP FLASH with 8KB RAM
• Manufacturer: Philips Semiconductors

1. Security bits are independent of each other. Full-chip erase may be performed regardless of the state of the security bits.
2. All other combination of lockbits is undefined.
3. Setting LBx doesn’t prevent programming of unprogrammed bits.
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 P89C668 has 3 programmable security lock bits that will provide different levels of protection for the on-chip code and data (see
Table 11).
Table 11.
NOTE:
2001 Jul 27
80C51 8-bit Flash microcontroller family
64KB ISP Flash with 8KB RAM
Level
1
2
3
4
SECURITY LOCK BITS
LB1
0
1
1
1
LB2
0
0
1
1
1
LB3
0
0
0
1
MOVC instructions executed from external program memory are disabled from fetching
code bytes from internal memory.
Same as level 1, plus block erase is disabled. Erase or programming of the status byte or
boot vector is disabled.
Same as level 2, plus verify of code memory is disabled.
Same as level 3, plus external execution is disabled.
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PROTECTION DESCRIPTION
PROTECTION DESCRIPTION
P89C668
Preliminary data