There are two names can be chose for this device, AM29F040-old
and AM29F040. When "COPY" command is executed, the "-old" name
will conduct an extra step of doing the Sector-Protect-Unprotect on the
chip.
Because some newer date-coded chip(dated after
3) have a
different Unprotect algorithm, the old algorithm will cause all eight
sectors been kept on "Protected" state, and causing the following erase
action fails. We strongly recommend that using the "AM29F040" name
to handle the newer date-coded chips. For those newer dated chips
which already been sector protected, it have to be unprotected on some
other programmer.
Both names will handle the post Sector-Protect action correctly, after
the copy was completed, according to the value in the PSB byte where
bit7 represent the highest sector and a "1" means "Protect".
The master IC's protection status will not be used. Instead, the PSB
was used in the COPY and VERIFY command.
1.
VERIFY: After the regular comparison on the memory array
completed, all the slave IC's protecting status will be compared with the
PSB setting. A slave IC will be acknowledged as a good one only both
comparing was passed. If the error LED lights at the last moment, it
mostly can say that the protection status is the only difference.
2.
COPY: The slave chips was erased first, then the master's contents
was copied to all slaves, then the sector protect was done according to
the PSB setting. At the last, the VERIFY action will taken. If the "-old"
name was chose, a Sector-Unprotect action will be conducted at the
very beginning, before the erase step.
The "AM29F040" name should be used for most chips, unless you
are sure the chip you have is of the older one.
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