Operating features
Table 2.
M25PE40
Software protection truth table (Sectors 0 to 7, 64-Kbyte granularity)
Sector Lock Register
Protection status
Lock
Write
Down bit Lock bit
Sector unprotected from Program/Erase/Write operations, protection status
reversible
0
0
1
1
0
1
0
1
Sector protected from Program/Erase/Write operations, protection status
reversible
Sector unprotected from Program/Erase/Write operations,
sector protection status cannot be changed except by a reset or power-up.
Sector protected from Program/Erase/Write operations,
sector protection status cannot be changed except by a reset or power-up.
■
The second Software Protected mode (SPM2) uses the Block Protect bits (BP2,
BP1, BP0, see Section 6.4.3)) to allow part of the memory to be configured as read-
only.
Table 3.
Protected area sizes
Status Register
content
Memory content
BP2 BP1 BP0
Protected area
Unprotected area
bit
bit
bit
0
0
0
0
0
1
none
All sectors(1) (eight sectors: 0 to 7)
Upper eighth (sector 7)
Lower seven-eighths (seven sectors: 0 to 6)
Upper quarter (two sectors: 6 and
7)
0
1
0
Lower three-quarters (six sectors: 0 to 5)
0
1
1
1
1
1
0
0
1
1
1
0
1
0
1
Upper half (four sectors: 4 to 7)
All sectors (eight sectors: 0 to 7)
All sectors (eight sectors: 0 to 7)
All sectors (eight sectors: 0 to 7)
All sectors (eight sectors: 0 to 7)
Lower half (four sectors: 0 to 3)
none
none
none
none
1. The device is ready to accept a Bulk Erase instruction if, and only if, all Block Protect bits (BP2, BP1, BP0)
are 0.
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NUMONYX [ NUMONYX B.V ]
