256Mb, 512Mb, 1Gb, 2Gb: 3V Embedded Parallel NOR Flash
Common Flash Interface
Common Flash Interface
The common Flash interface (CFI) is a JEDEC-approved, standardized data structure
that can be read from the Flash memory device. It allows a system's 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 de-
vice, enabling the software to upgrade itself when necessary.
When the READ CFI command is issued, the device enters CFI query mode and the data
structure is read from memory. The following tables show the addresses (A-1, A[7:0])
used to retrieve the data. The query data is always presented on the lowest order data
outputs (DQ[7:0]), and the other data outputs (DQ[15:8]) are set to 0.
Table 17: Query Structure Overview
Note 1 applies to the entire table
Address
x16
10h
1Bh
27h
40h
x8
20h
36h
4Eh
80h
Subsection Name
CFI query identification string
System interface information
Device geometry definition
Primary algorithm-specific extended query table
Note:
Description
Command set ID and algorithm data offset
Device timing and voltage information
Flash device layout
Additional information specific to the primary al-
gorithm (optional)
1. Query data are always presented on the lowest order data outputs (DQ[7:0]). DQ[15:8]
are set to 0.
Table 18: CFI Query Identification String
Note 1 applies to the entire table
Address
x16
10h
11h
12h
13h
14h
15h
16h
17h
18h
19h
1Ah
x8
20h
22h
24h
26h
28h
2Ah
2Ch
2Eh
30h
32h
34h
Data
0051h
0052h
0059h
0002h
0000h
0040h
0000h
0000h
0000h
0000h
0000h
Note:
Primary algorithm command set and control interface ID code 16-bit ID
code defining a specific algorithm
Address for primary algorithm extended query table (see the Primary Algo-
rithm-Specific Extended Query Table)
Alternate vendor command set and control interface ID code second ven-
dor-specified algorithm supported
Address for alternate algorithm extended query table
Description
Query unique ASCII string "QRY"
Value
"Q"
"R"
"Y"
–
P = 40h
–
–
1. Query data are always presented on the lowest order data outputs (DQ[7:0]). DQ[15:8]
are set to 0.
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