M29W008EB データシートの表示（PDF） - STMicroelectronics
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M29W008EB Datasheet PDF : 43 Pages
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M29W008ET, M29W008EB
3 Bus Operations
3.2 Special bus operations
Additional bus operations can be performed to read the Electronic Signature and also to apply
and remove Block Protection. These bus operations are intended for use by programming
equipment and are not usually used in applications. They require VID to be applied to some
pins.
3.2.1
Read Electronic Signature
The memory has two codes, the Manufacturer code and the Device code, that can be read to
identify the memory.
These codes allow programming equipment or applications to automatically match their
interface to the characteristics of the M29W008E.
The electronic Signature is output either by applying the signals listed in Table 2: Bus
Operations or by issuing an Auto Select command (see Section 4.2: Auto Select command).
3.2.2
Block Protection and Unprotection
Each block can be individually protected against accidental Program or Erase using
programming equipment. Protected blocks can be unprotected to allow data to be changed.
There are two methods available for protecting and unprotecting the blocks, one for use on
programming equipment (Programmer Technique) and the other for in-system use (In-System
Technique). Block Protect and Chip Unprotect operations are described in Appendix B: Block
protection.
Table 2. Bus Operations
Operation
E G W RP
Address Inputs A0-A19
DQ0-
DQ7
Byte Read
VIL VIL VIH VIH
Cell Address
Data
Output
Byte Write
VIL VIH VIL VIH
Command Address
Data
Input
Output Disable
VIL VIH VIH VIH
X
Hi-Z
Standby
VIH X(1) X(1) VIH
X
Hi-Z
Read
Manufacturer Code
VIL VIL
VIH
VIH
A0= VIL, A1= VIL, A9=VID,
others address bits are ‘Don’t Care’
20h
Electronic
signature
Device M29W008ET
Code M29W008EB
VIL
VIL
VIH
VIH
A0= VIH, A1= VIL, A9=VID,
others address bits are ‘Don’t Care’
D2h
DCh
1. X = VIL or VIH.
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