Signature

Documents signature bytes used on EPROM, AT89C51, 87C51, etc.

https://www.jedec.org/standards-documents/docs/jep-106ab

Is AT89C51 signature the same as P87C51 signature?

Do mcs51 mask ROM parts support signature?

Are EPROM signatures compatible with mcs51 signatures in any way?

89C51 family

IDs are found at special NV memory address 0x30-0x32

ID (hex)	Vendor	Chip label	Die ID
row 1, cell 1	row 1, cell 2	row 1, cell 3	row 1, cell 3
row 2, cell 1	row 2, cell 2	row 2, cell 3	row 2, cell 3