TO HOME PAGEAm29F040 Operation Note:
There are two names can be chose for this device, AM29F040-01 and AM29F040-03. When "COPY" command is executed, the -01 has an extra step doing the Sector Protect/Unprotect onto this chip. Because of the PROM8908D will not handle this feature properly on some newer date-code chips, all eight sectors will become Protected and causing the following ChipErase action fails.
We strongly recommend the user using the AM29F040-03 name to do his work. For those devices which had already been Sector-Protected, UnProtected them first at some other places before hand them to the PROM8908D.
Both names can handle the post Sector-Protect action correctly after the copy is 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 compare on memory array was completed, all the slave IC's protecting status will be compared with the PSB settings. A slave IC will be acknowledged as a good one only both comparing was passed. If the error LED turn-on at the last moment, it mostly can be said that only the protection state is different.
1. COPY: If "-01" was chose, the Sector-Unprotect action will be done first. Then, the master's contents was copied to all slaves, the Sector-Protect was done again according to user's PSB setting. At last, the VERIFY action was executed auto.
2. COPY: If "-03" was chose, the Sector-Unprotect action will be by-passed. The PROM8908 doesn't support this action on the AMD's new die which this algorithm had been modified. If the user has an already-erased chip on hand, the -03 should be used to do all the programming.