39/53
M28W320CT, M28W320CB
APPENDIX B. COMMON FLASH INTERFACE (CFI)
TheCommonFlashInterfaceisaJEDECap-
proved, 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 mem-
ory. The system can interface easily with the de-
vice, enabling the software to upgrade itself when
necessary.
When the CFI Query Command (RCFI) is issued
the device enters CFI Query mode and the data
structure is read from the memory. Tables 27, 28,
29, 30, 31 and 32 show the addresses used to re-
trieve the data.
The CFI data structure also contains a security
area where a 64 bit unique security number is writ-
ten (see Table 32, Security Code area). This area
can be accessed only in Read mode by the final
user. It is impossible to change the security num-
ber after it has been written by ST. Issue a Read
command to return to Read mode.
Table 27. Query Structure Overview
Note: Query data are always presented on the lowest order data outputs.
Table 28. CFI Query Identification String
Note: Query data are always presented on the lowest order data outputs (DQ7-DQ0) only. DQ8-DQ15 are ‘0’.
Offset Sub-section Name Description
00h Reserved Reserved for algorithm-specific information
10h CFI Query Identification String Command set ID and algorithm data offset
1Bh System Interface Information Device timing & voltage information
27h Device Geometry Definition Flash device layout
P Primary Algorithm-specific Extended Query table
Additional information specific to the Primary
Algorithm (optional)
A Alternate Algorithm-specific Extended Query table
Additional information specific to the Alternate
Algorithm (optional)
Offset Data Description Value
00h 0020h Manufacturer Code ST
01h
88BAh
88BBh
Device Code
Top
Bottom
02h-0Fh reserved Reserved
10h 0051h "Q"
11h 0052h Query Unique ASCII String "QRY" "R"
12h 0059h "Y"
13h 0003h
Primary Algorithm Command Set and Control Interface ID code 16 bit ID code
defining a specific algorithm
Intel
compatible
14h 0000h
15h 0035h
Address for Primary Algorithm extended Query table (see Table 30) P = 35h
16h 0000h
17h 0000h
Alternate Vendor Command Set and Control Interface ID Code second vendor -
specified algorithm supported (0000h means none exists)
NA
18h 0000h
19h 0000h
Address for Alternate Algorithm extended Query table
(0000h means none exists)
NA
1Ah 0000h
