Common Flash Interface (CFI)
M29W320ET, M29W320EB
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. Table 22, Table 23, Table 24, Table 25, Table 26 and Table 27 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 Table 27: Security code area). 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.
(1)
Table 22. Query Structure Overview
Address
Sub-section name
Description
x16
x8
10h
1Bh
27h
20h
36h
4Eh
CFI Query Identification String
System Interface Information
Device Geometry Definition
Command set ID and algorithm data offset
Device timing & voltage information
Flash device layout
Primary Algorithm-specific extended
Query table
Additional information specific to the Primary
Algorithm (optional)
40h
61h
80h
C2h
Security code area
64 bit unique device number
1. Query data are always presented on the lowest order data outputs.
(1)
Table 23. CFI Query Identification String
Address
Data
Description
Value
x16
x8
10h
11h
12h
13h
14h
15h
16h
17h
18h
19h
1Ah
20h
22h
24h
26h
28h
2Ah
2Ch
2Eh
30h
32h
34h
0051h
“Q”
"R"
"Y"
0052h Query unique ASCII string "QRY"
0059h
0002h
AMD
Primary Algorithm Command Set and Control Interface ID code 16 bit
ID code defining a specific algorithm
Compatible
0000h
0040h
Address for Primary Algorithm extended query table (see Table 26)
P = 40h
NA
0000h
0000h
Alternate Vendor Command Set and Control Interface ID code second
vendor - specified algorithm supported
0000h
0000h
Address for Alternate Algorithm extended Query table
0000h
NA
1. Query data are always presented on the lowest order data outputs (DQ7-DQ0) only. DQ8-DQ15 are ‘0’.
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