Bus Operations
M29FxxxFT, M29FxxxFB
3.5
Automatic Standby
If CMOS levels (V ± 0.2V) are used to drive the bus and the bus is inactive for 150ns or
CC
more the memory enters Automatic Standby where the internal Supply Current is reduced to
the Standby Supply Current, I
. The Data Inputs/Outputs will still output data if a Bus
CC2
Read operation is in progress.
3.6
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 V to be
ID
applied to some pins.
3.7
3.8
Electronic Signature
The memory has two codes, the manufacturer code and the device code, that can be read
to identify the memory. These codes can be read by applying the signals listed in Table 2.:
Bus Operations, BYTE = VIL and Table 3.: Bus Operations, BYTE = VIH.
Block Protection and Block Unprotection
Each block can be separately protected against accidental Program or Erase. 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 and the other for in-system use. Block Protect and Blocks
Unprotect operations are described in Appendix C: Block protection.
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NUMONYX [ NUMONYX B.V ]
