Common Flash Interface (CFI)
M29W320DT, M29W320DB
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 21, Table 22, Table 23, Table 24, Table 25 and
Table 26 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 26, 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. Issue a Read
command to return to Read mode.
(1)
Table 21. Query Structure Overview
Address
Sub-section Name
Description
x16
x8
10h
1Bh
27h
20h CFI Query Identification String
36h System Interface Information
4Eh Device Geometry Definition
Command set ID and algorithm data offset
Device timing & voltage information
Flash device layout
Additional information specific to the Primary
Algorithm (optional)
40h
61h
80h Primary Algorithm-specific Extended Query table
C2h Security Code Area
64 bit unique device number
1. Query data are always presented on the lowest order data outputs.
(1)
Table 22. 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
Primary Algorithm Command Set and Control Interface ID code 16 bit
ID code defining a specific algorithm
AMD Compatible
0000h
0040h
Address for Primary Algorithm extended Query table (see Table 24)
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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