SR176A4T1GE STMicroelectronics, SR176A4T1GE Datasheet - Page 21

• Manufacturer Part Number: SR176A4T1GE
• Manufacturer: STMicroelectronics

Specifications of SR176A4T1GE

• Operating Temperature (max): 85C
• Operating Temperature Classification: Commercial
• Lead Free Status / RoHS Status: Compliant

SR176
5.7
PROTECT_BLOCK
Command Code = 09h,0Fh,00h,LOCK_REG
Prior to any PROTECT_BLOCK command, the SR176 must have been set into the
SELECTED state.
The PROTECT_BLOCK command allows the write access to be blocked to memory blocks
4 to 15. It must be followed by a SELECT() command. This re-initializes the write protection
conditions to blocks 4 to 15. Until then, the new protection setting is not taken into account
by the SR176 logic. The SR176 does not generate any response when it executes a
PROTECT_BLOCK command
command to get the information on the protection status.
The OTP LOCK_REG controls the write-protection on blocks 4 to 15, and is, itself, One-
Time Programmable. Each ‘1’ in the LOCK_REG parameter indicates that the
corresponding bit in the OTP LOCK_REG should be set. Each ‘0’ indicates that the
corresponding bit should be left unchanged. Once a bit in the OTP LOCK_REG has been
set to ‘1’, it is not possible to reset it to ‘0’ and the corresponding memory blocks are forever
write protected (and behaves like ROM).
Request parameters
Figure 31. PROTECT_BLOCK request format
Table 3.
Parameter Bit
Lock Reg
LOCK_REG
SOF
b
b
b
b
b
b
b
b
7
6
5
4
3
2
1
0
Bits in the LOCK_REG parameter, and in the OTP LOCK_REG Register
09h
1: set b
0: leave it unchanged
1: set b
0: leave it unchanged
1: set b
0: leave it unchanged
1: set b
0: leave it unchanged
1: set b
0: leave it unchanged
1: set b
0: leave it unchanged
1: set b
0: leave it unchanged
1: set b
0: leave it unchanged
(Table
PROTECT_BLOCK
(Figure
15
14
13
12
11
10
9
8
of Block 15 to ‘1’
of Block 15 to ‘1’
Meaning
3)
of Block 15 to ‘1’
of Block 15 to ‘1’
of Block 15 to ‘1’
of Block 15 to ‘1’
of Block 15 to ‘1’
of Block 15 to ‘1’
0Fh
31):
(Figure
00h
32). The reader must use the GET_PROTECTION
LOCK_REG
Block 15 Bit
8 bIts
b
b
b
b
b
b
b
b
15
14
13
12
11
10
9
8
Device operations (instructions)
CRC L
8 bIts
1: Write-Protect Blocks 14 and 15
0: Allow write access
1: Write-Protect Blocks 12 and 13
0: Allow write access
1: Write-Protect Blocks 10 and 11
0: Allow write access
1: Write-Protect Blocks 8 and 9
0: Allow write access
1: Write-Protect Blocks 6 and 7
0: Allow write access
1: Write-Protect Blocks 4 and 5
0: Allow write access
1: Write-Protect Blocks 2 and 3
0: Allow write access
1: Write-Protect Blocks 0 and 1
0: Allow write access
CRC H
8 bIts
Meaning
AI07711B
EOF
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