Common Flash Interface (CFI)
M29FxxxFT, M29FxxxFB
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
and
Table 35. 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
Table 35., 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.
Note:
The Common Flash Interface is only available for Temperature range 6 (–40 to 85 °C).
Table 30.
Query Structure Overview
Query data are always presented on the lowest order data outputs.
Table 31.
CFI Query Identification String
Query data are always presented on the lowest order data outputs (DQ7-DQ0) only. DQ8-DQ15 are ‘0’.
Address
Sub-section Name
Description
x16
x8
10h
20h
CFI Query Identification String
Command set ID and algorithm data offset
1Bh
36h
System Interface Information
Device timing & voltage information
27h
4Eh
Device Geometry Definition
Flash device layout
40h
80h
Primary Algorithm-specific Extended
Query table
Additional information specific to the Primary Algorithm
(optional)
61h
C2h
Security Code Area
64 bit unique device number
Address
Data
Description
Value
x16
x8
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
ID code defining a specific algorithm
AMD
Compatible
14h
28h
0000h
15h
2Ah
0040h
Address for Primary Algorithm extended Query table (see Table
P = 40h
16h
2Ch
0000h
17h
2Eh
0000h
Alternate Vendor Command Set and Control Interface ID Code
second vendor - specified algorithm supported
NA
18h
30h
0000h
19h
32h
0000h
Address for Alternate Algorithm extended Query table
NA
1Ah
34h
0000h