s-25a080a Seiko Instruments Inc., s-25a080a Datasheet - Page 13

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

Rev.1.0
125°C OPERATION SPI SERIAL E
1. Status register
Operation
1. 1 SRWD (b7) : Status Register Write Disable
1. 2 BP1, BP0 (b3, b2) : Block Protect
1. 3 WEL (b1) : Write Enable Latch
The status register’s organization is below. The status register can Write and Read by a specific instruction.
The status/control bits of the status register are as follows.
Bit SRWD operates in conjunction with the Write protect signal ( WP ). With a combination of bit SRWD and signal
nonvolatile bit in the status register (SRWD, BP1, BP0) go in Read Only, so that the WRSR instruction is not be
performed.
Bit BP1 and BP0 are composed of the nonvolatile bit. The area size of Software Protect against WRITE instruction
is defined by them. Rewriting these bits is possible by the WRSR instruction. To protect the memory area against
the WRITE instruction, set either or both of bit BP1 and BP0 to “1”. Rewriting bit BP1 and BP0 is possible unless
they are in Hardware Protect mode. Refer to “ Protect Operation” for details of “Block Protect”.
Bit WEL shows the status of internal Write Enable Latch. Bit WEL is set by the WREN instruction only. If bit WEL is
“1”, this is the status that Write Enable Latch is set. If bit WEL is “0”, Write Enable Latch is in reset, so that the S-
25A080A/160A/320A does not receive the WRITE or WRSR instruction. Bit WEL is reset after these operations;
• The power supply voltage is dropping
• Power-on
• After performing WRDI
• After the Write operation by the WRSR instruction
• After the Write operation by the WRITE instruction
WP (SRWD = “1”, WP = “L”), this device goes in Hardware Protect status. In this case, the bits composed of the
_00
Status Register Write Disable
SRWD
b7
b6
0
Figure 8 Organization of Status Register
Block Protect Bits
b5
0
2
PROM FOR AUTOMOTIVE ELECTRIC COMPONENT
Seiko Instruments Inc.
b4
0
BP1
b3
BP0
b2
Write Enable Latch
WEL
b1
S-25A080A/160A/320A
Write In Progress
WIP
b0
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