M28W320FCT datasheet(51/69 Pages) STMICROELECTRONICS

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M28W320FCT, M28W320FCB

Common Flash Interface (CFI)

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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 (RCFI) is issued the device enters CFI Query mode and the

data structure is read from the memory. Table 26, Table 27, Table 28, Table 29, Table 30 and

Table 31 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 31: 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 ST. Issue a Read command to return to Read mode.

Table 26.

Query Structure Overview(1)

Offset

Sub-section Name

Description

00h

Reserved

Reserved for algorithm-specific information

10h

CFI Query Identification String

Command set ID and algorithm data offset

1Bh

System Interface Information

Device timing & voltage information

27h

Device Geometry Definition

Flash device layout

Primary Algorithm-specific Extended Query table

Additional information specific to the Primary

Algorithm (optional)

Alternate Algorithm-specific Extended Query table

Additional information specific to the Alternate

Algorithm (optional)

Query data are always presented on the lowest order data outputs.

Table 27.

CFI Query Identification String(1)

Offset

Data

Description

Value

00h

0020h

Manufacturer Code

01h

88BAh

88BBh

Device Code

Top

Bottom

02h-0Fh reserved Reserved

10h

0051h

"Q"

11h

0052h

Query Unique ASCII String "QRY"

"R"

12h

0059h

"Y"

13h

0003h

Primary Algorithm Command Set and Control Interface ID code 16 bit

ID code defining a specific algorithm

Intel compatible

14h

0000h

15h

0035h

Address for Primary Algorithm extended Query table (see Table 29)

P = 35h

16h

0000h

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