p87c51mc2 NXP Semiconductors, p87c51mc2 Datasheet - Page 17

• Manufacturer Part Number: p87c51mc2
• Description: 80c51 8-bit Microcontroller Family With Extended Memory
• Manufacturer: NXP Semiconductors

SECURITY BITS
The P87C51Mx2 has security bits to protect users’ firmware codes. With none of the security bits programmed, the code in the
program memory can be verified. With only security bit 1 (see Table 6) is programmed, MOVC instructions executed from
external program memory are disabled from fetching code bytes from the internal memory. EA is latched on Reset and all further
programming of EPROM is disabled. When security bits 1 and 2 are programmed, in addition to the above, verify mode is
disabled. When all three security bits are programmed, all of the conditions above apply and all external program memory
execution is disabled.
Table 6: EPROM Security Bits
2001 Apr 06
Philips Semiconductors
Notes:
1. P - programmed. U- unprogrammed.
2. Any other combination of security bits is not defined.
80C51 8-bit microcontroller family with extended memory
64KB/96KB OTP with 2KB/3KB RAM
1
2
3
4
Security Bits
Bit 1
U
P
P
P
Bit 2
U
U
P
P
1,2
Bit 3
U
U
U
P
Protection Description
No program security features enabled. EEPROM is programmable and verifiable.
MOVC instructions executed from external program memory are disabled from fetching
code bytes from internal memory, EA is sampled and latched on Reset, and further
programming of the EPROM is disabled.
Same as 2, also verification is disabled.
Same as 3, external execution is disabled.
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P87C51MB2/P87C51MC2
Preliminary specification