6.4.2 Write-Protect Enable Function
The WRSR
instruction also allows the user to enable or
disable the Write-Protect (WP) pin through the use of the
Write-Protect Enable (WPEN) bit. When the WPEN bit is set to logic ‘0
’,
the ability to write the EEPROM array is dictated by the values of the Block
Write-Protect (BP1, BP0) bits. The ability to write the STATUS register is controlled by
the WEL bit. When the WPEN bit is set to logic ‘1
’, the STATUS register
is read-only.
Hardware Write Protection is enabled when both the
WP pin is low and the WPEN bit has been set to a logic
‘1
’. When the device is Hardware Write‑Protected, writes to the
STATUS register, including the Block Write‑Protect, WEL and WPEN bits and to the
sections in the memory array selected by the Block Write‑Protect bits are disabled. When
Hardware Write Protection is enabled, writes are only allowed to sections of the memory
that are not block‑protected.
Hardware Write Protection is disabled when either the
WP pin is high or the WPEN bit is a logic
‘0
’. When Hardware Write Protection is disabled, writes are only
allowed to sections of the memory that are not block‑protected. Refer to Table 6-5 for additional information.
0
’ as long as
the WP pin is held low.WPEN | WP Pin | WEL | Protected Blocks | Unprotected Blocks | STATUS Register |
---|---|---|---|---|---|
0 | x | 0 | Protected | Protected | Protected |
0 | x | 1 | Protected | Writable | Writable |
1 | Low | 0 | Protected | Protected | Protected |
1 | Low | 1 | Protected | Writable | Protected |
x | High | 0 | Protected | Protected | Protected |
x | High | 1 | Protected | Writable | Writable |