M29W128 View Datasheet(PDF) - Numonyx -> Micron
Part Name
Description
Manufacturer
M29W128 Datasheet PDF : 78 Pages
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M29W128FH, M29W128FL
Bus operations
3.5
Automatic Standby
If CMOS levels (VCC ± 0.3V) are used to drive the bus and the bus is inactive for tAVQV+
30ns or more the memory enters Automatic Standby where the internal Supply Current is
reduced to the Standby Supply Current, ICC2. The Data Inputs/Outputs will still output data if
a Bus Read operation is in progress.
3.6
3.6.1
3.6.2
3.6.3
3.6.4
Special Bus operations
Additional bus operations can be performed to read the Electronic Signature, verify the
Protection Status of the Extended Memory Block, and 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.
Read Electronic Signature
The memory has two codes, the Manufacturer code and the Device code used to identify
the memory. These codes can accessed by performing read operations with control signals
and addresses set as shown in Table 3 and Table 5.
These codes can also be accessed by issuing an Auto Select command (see Section 5.1.2:
Auto Select command).
Verify Extended Memory Block Protection Indicator
The Extended Memory Block is either Factory Locked or Customer Lockable.
The Protection Status of the Extended Memory Block (Factory Locked or Customer
Lockable) can be accessed by reading the Extended Memory Block Protection Indicator.
This is performed by applying the signals as shown in Table 4 and Table 7. The Protection
Status of the Extended Memory Block is then output on bit DQ7 of the Data Input/Outputs.
(see Table 2 and Table 5, Bus Operations).
The Protection Status of the Extended Memory Block can also be accessed by issuing an
Auto Select command (see Section 5.1.2: Auto Select command).
Verify Block Protection Status
The Protection Status of a Block can be directly accessed by performing a read operation
with control signals and addresses set as shown in Table 4 and Table 7.
If the Block is protected, then 01h (in x8 mode) is output on Data Input/Outputs DQ0-DQ7,
otherwise 00h is output.
Hardware Block Protect
The VPP/WP pin can be used to protect the highest or lowest block. When VPP/WP is at VIL
the highest or lowest block is protected and remains protected regardless of the Block
Protection Status or the Reset/Block Temporary Unprotect pin state.
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