M29DW640D Datasheet, PDF (44/56 Pages) STMicroelectronics – 64 Mbit (8Mb x8 or 4Mb x16, Multiple Bank, Page, Boot Block) 3V Supply Flash Memory

M29DW640D
APPENDIX B. COMMON FLASH INTERFACE (CFI)
The Common Flash Interface is a JEDEC ap-
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 Read CFI Query command is issued the
addressed bank enters Read CFI Query mode and
read operations in the same bank (A21-A19) out-
put the CFI data. Tables 24, 25, 26, 27, 28 and 29
show the addresses (A-1, A0-A10) used to retrieve
the data.
The CFI data structure also contains a security
area where a 64 bit unique security number is writ-
ten (see Table 29., 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.
Table 24. Query Structure Overview
Address
x16
x8
Sub-section Name
10h
20h
CFI Query Identification String
1Bh
36h
System Interface Information
27h
4Eh
Device Geometry Definition
40h
80h
Primary Algorithm-specific Extended
Query table
61h
C2h
Security Code Area
Note: Query data are always presented on the lowest order data outputs.
Description
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
Table 25. CFI Query Identification String
Address
x16
x8
Data
Description
Value
10h
20h
0051h
“Q”
11h
22h
0052h Query Unique ASCII String "QRY"
"R"
12h
24h
0059h
"Y"
13h
26h
0002h _{Primary Algorithm Command Set and Control Interface ID code 16 bit}
AMD
14h
28h
0000h ^{ID code defining a specific algorithm}
Compatible
15h
2Ah
0040h
Address for Primary Algorithm extended Query table (see Table 28)
16h
2Ch
0000h
P = 40h
17h
18h
2Eh
0000h _{Alternate Vendor Command Set and Control Interface ID Code second}
30h
0000h ^{vendor - specified algorithm supported}
NA
19h
32h
0000h _{Address for Alternate Algorithm extended Query table}
NA
1Ah
34h
0000h
Note: Query data are always presented on the lowest order data outputs (DQ7-DQ0) only. DQ8-DQ15 are ‘0’.
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