s-25a080a Seiko Instruments Inc., s-25a080a Datasheet - Page 22

• Manufacturer Part Number: s-25a080a
• Description: 25?c Operation Spi Serial E2prom For Automotive Electric Component
• Manufacturer: Seiko Instruments Inc.

22
125°C OPERATION SPI SERIAL E
S-25A080A/160A/320A
Remark X = Don’t care
Software Protect
(SPM)
Hardware Protect
(HPM)
Protect Operation
Table 16 shows the block settings of Write protect. Table 17 shows the protect operation for the device. As long as bit
SRWD, the Status Register Write Disable bit, in the status register is reset to “0” (it is in reset before the shipment), the
value of status register can be changed.
These are two statuses when bit SRWD is set to “1”.
• Write in the status register is possible; Write protect ( WP ) is in “H”.
• Write in the status register is impossible; Write protect ( WP ) is in “L”. Therefore the Write protect area which is set by
protect bit (BP1, BP0) in the status register cannot be changed.
These operations are to set Hardware Protect (HPM).
• After setting bit SRWD, set Write protect ( WP ) to “L”.
• Set bit SRWD completed setting Write protect ( WP ) to “L”.
Figure 6 and 7 show the Valid timing in Write protect and Invalid timing in Write protect during the cycle Write to the
status register.
By inputting “H” to Write protect ( WP ), Hardware Protect (HPM) is released. If the Write protect ( WP ) is “H”, Hardware
Protect (HPM) does not function, Software Protect (SPM) which is set by the protect bits in the status register (BP1,
BP0) only works.
BP1
Mode
0
0
1
1
Status register
BP0
WP pin
0
1
0
1
X
X
1
1
0
0
Bit SRWD
The area of Write protect
Table 16 The Block Settings of Write Protect
X
X
0
0
1
1
100 %
25 %
50 %
Table 17 Protect Operation
0 %
2
PROM FOR AUTOMOTIVE ELECTRIC COMPONENT
Bit WEL
Seiko Instruments Inc.
0
1
0
1
0
1
Write protect block
Write disable
Write disable
Write disable
Write disable
Write disable
Write disable
S-25A080A
300h-3FFh
200h-3FFh
000h-3FFh
None
Address of Write protect block
General block
Write disable
Write disable
Write disable
Write enable
Write enable
Write enable
S-25A160A
600h-7FFh
400h-7FFh
000h-7FFh
None
C00h to FFFh
800h to FFFh
000h to FFFh
Status register
S-25A320A
Write disable
Write disable
Write disable
Write disable
Write enable
Write enable
None
Rev.1.0
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