M29W064FT, M29W064FB
Common Flash interface (CFI)
Appendix B
Common Flash interface (CFI)
The common Flash interface is a JEDEC approved, standardized data structure that can be
read from the Flash memory device. It allows a system software to query the device to
determine various electrical and timing parameters, density information and functions
supported by the memory. The system can interface easily with the device, enabling the
software to upgrade itself when necessary.
When the CFI Query command is issued the device enters CFI query mode and the data
structure is read from the memory. Tables
and
show the addresses
used to retrieve the data.
The CFI data structure also contains a security area where a 64-bit unique security number
is written (see
This area can be accessed only in read mode
by the final user. It is impossible to change the security number after it has been written by
Numonyx.
Table 22.
Address
Sub-section name
x 16
10h
1Bh
27h
40h
61h
x8
20h
36h
4Eh
80h
C2h
CFI query identification string
System interface information
Device geometry definition
Primary algorithm-specific extended
query table
Security code area
Command set ID and algorithm data offset
Device timing & voltage information
Flash device layout
Additional information specific to the
primary algorithm (optional)
64-bit unique device number
Description
Query structure overview
(1)
1. Query data are always presented on the lowest order data outputs.
55/69
NUMONYX [ NUMONYX B.V ]
