M29W800AT Datasheet, PDF (27/33 Pages) STMicroelectronics – 8 Mbit 1Mb x8 or 512Kb x16, Boot Block Low Voltage Single Supply Flash Memory

M29W800AT, M29W800AB
SECURITY PROTECTION MEMORY AREA
The M29W800A features a security protection
memory area. It consists of a memory block of 256
bytes or 128 words which is programmed in the ST
factory to store a unique code that uniquely identi-
fies the part.
This memory block can be read by using the Read
Security Data instruction (RDS) as shown in Table
24.
Read Security Data (RDS) Instruction. This RDS
uses a single write cycle instruction: the command
B8h is written to the address AAh. This sets the
memory to the Read Security mode. Any succes-
sive read attempt will output the addressed Secu-
rity byte until a new write cycle is initiated.
Table 24. Security Block Instruction
Mne.
Instr.
Cyc.
Unlock Cycle
1st Cyc.
2nd Cyc.
RDS
Read
Security
Data
Addr. ⁽¹⁾
1
Data ⁽²⁾
AAh
Read OTP Data until a new write cycle is initiated.
B8h
Note: 1. Address bits A10-A19 are don’t care for coded address inputs.
2. Data bits DQ8-DQ15 are don’t care for coded address inputs.
Figure 15. Security Block Address Table
000FFh
00000h
BYTE Organisation (x8)
TOP BOOT BLOCK
BOTTOM BOOT BLOCK
Security
Memory Block
Security
Memory Block
0E0FFh
0E000h
0007Fh
00000h
WORD Organisation (x16)
TOP BOOT BLOCK
BOTTOM BOOT BLOCK
Security
Memory Block
Security
Memory Block
0E01Fh
0E000h
AI02746
27/33