T89C5115 ATMEL Corporation, T89C5115 Datasheet - Page 36

• Manufacturer Part Number: T89C5115
• Description: Low Pin Count 8-bit MCU with A/D Converter and 16-Kbytes of Flash Memory
• Manufacturer: ATMEL Corporation

Flash Protection from Parallel
Programming
Preventing Flash Corruption
36
T89C5115
Figure 15. Reading Procedure
The three lock bits in Hardware Security Byte (see "In-System Programming" section)
are programmed according to Table 22 provide different level of protection for the on-
chip code and data located in FM0 and FM1.
The only way to write this bits are the parallel mode. They are set by default to level 3.
Table 22. Program Lock bit
Program Lock bits
U: unprogrammed
P: programmed
WARNING: Security level 2 and 3 should only be programmed after Flash and Core
verification.
See paragraph in the "Power Management" section, page 17.
Security
level
1
2
3
Program Lock Bits
LB0
U
P
U
LB1
U
U
P
LB2
U
U
U
Protection Description
No program lock features enabled. MOVC instruction executed from
external program memory returns non encrypted data.
Parallel programming of the Flash is disabled.
Same as 2, also verify through parallel programming interface is
disabled.
Flash Spaces Reading
Exec: MOVC A, @A+DPTR
Flash Spaces Mapping
FCON= 00000xx0b
DPTR= Address
FCON = 00h
Clear Mode
Data Read
ACC= 0
4128A–8051–04/02