256Mb: 3V Embedded Parallel NOR Flash
Common Flash Interface
Common Flash Interface
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 Read CFI Query command is issued, the memory enters read CFI query mode
and read operations output the CFI data. The tables here show the addresses (A0-A7)
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 40: Security Code Area). This area
can be accessed only in read mode by the final user. It is impossible to change the se-
curity number after it has been written by Micron.
Table 22: Query Structure Overview
Note applies to the entire table.
Address
x16
Sub-section name
Description
10h
1Bh
27h
40h
CFI query identification string
System interface information
Command set ID and algorithm data offset
Device timing & voltage information
Flash device layout
Device geometry definition
Primary algorithm-specific extended query table
Additional information specific to the primary
algorithm (optional)
61h
Security code area
64-bit unique device number
1. Query data are always presented on the lowest order data outputs.
Note:
Table 23: CFI Query Identification String
Note applies to the entire table.
Address
x16
10h
11h
12h
13h
14h
15h
16h
17h
18h
19h
1Ah
Data
0051h
0052h
0059h
0002h
0000h
0040h
0000h
0000h
0000h
0000h
0000h
Description
Value
‘Q’
Query unique ASCII string ‘QRY’
‘R’
‘Y’
Primary algorithm command set and control interface ID code 16 bit
ID code defining a specific algorithm
Spansion
compatible
Address for primary algorithm extended query table (see the Primary
Algorithm-Specific Extended Query Table)
P = 40h
NA
Alternate vendor command set and control interface ID code second
vendor - specified algorithm supported
Address for alternate algorithm extended query table
NA
1. Query data are always presented on the lowest order data outputs (DQ7-DQ0) only.
DQ8-DQ15 are ‘0’.
Note:
PDF: 09005aef84ecabef
m29dw_256g.pdf - Rev. A 10/12 EN
Micron Technology, Inc. reserves the right to change products or specifications without notice.
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