ez80f91 ZiLOG Semiconductor, ez80f91 Datasheet - Page 115

• Manufacturer Part Number: ez80f91
• Description: Ez80 Acclaimplus!? Connectivity Assp Ez80f91 Assp
• Manufacturer: ZiLOG Semiconductor

PS027001-0707
Note:
Flash Write/Erase Protection Register
The Flash Write/Erase Protection register prevents accidental Write or Erase operations.
The protection is limited to a resolution of eight 32 KB blocks. Setting a bit to 1 protects
that 32 KB block of Flash memory from accidental Writes or Erases. The default upon
RESET is for all Flash memory blocks to be protected.
The WP pin works in conjunction with FLASH_PROT[0] to protect the lowest block (also
called the Boot block) of Flash memory. If either the WP is held asserted or
FLASH_PROT[0] is set, the Boot block is protected from Write and Erase operations.
A protect bit is not available for the information page. The information page is, however,
protected excluded from a MASS ERASE by clearing the FLASH_PAGE register
(0x00FC) bit7(INFO_EN).
Writes to this register is allowed only after it is unlocked via the FLASH_KEY register.
Any attempted Writes to this register while locked will set it to
blocks. See
Table 41. Flash Write/Erase Protection Register
Bit
Reset
CPU Access
Note: R/W = Read/Write if unlocked, R = Read Only if locked. *Key sequence required to unlock.
Bit Position
[7]
BLK7_PROT
[6]
BLK6_PROT
[5]
BLK5_PROT
[4]
BLK4_PROT
[3]
BLK3_PROT
[2]
BLK2_PROT
Table
41.
Value Description
0
1
0
1
0
1
0
1
0
1
0
1
R/W*
Disable Write/Erase Protect on block 38000h to 3FFFFh.
Enable Write/Erase Protect on block 38000h to 3FFFFh.
Disable Write/Erase Protect on block 30000h to 37FFFh.
Enable Write/Erase Protect on block 30000h to 37FFFh.
Disable Write/Erase Protect on block 28000h to 2FFFFh.
Enable Write/Erase Protect on block 28000h to 2FFFFh.
Disable Write/Erase Protect on block 20000h to 27FFFh.
Enable Write/Erase Protect on block 20000h to 27FFFh.
Disable Write/Erase Protect on block 18000h to 1FFFFh.
Enable Write/Erase Protect on block 18000h to 1FFFFh.
Disable Write/Erase Protect on block 10000h to 17FFFh.
Enable Write/Erase Protect on block 10000h to 17FFFh.
7
1
R/W*
6
1
R/W*
5
1
R/W*
4
1
(FLASH_PROT = 00FAh)
R/W*
3
1
FFh
Product Specification
, thereby protecting all
R/W*
2
1
eZ80F91 ASSP
R/W*
1
1
Flash Memory
R/W*
0
1
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