M29DW323DT datasheet(39/49 Pages) STMICROELECTRONICS

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M29DW323DT, M29DW323DB

APPENDIX B. COMMON FLASH INTERFACE (CFI)

The Common Flash Interface is a JEDEC ap-

proved, 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 mem-

ory. The system can interface easily with the de-

vice, enabling the software to upgrade itself when

necessary.

When the CFI Query Command is issued the de-

vice enters CFI Query mode and the data structure

is read from the memory. Tables 23, 24, 25, 26, 27

and 28 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 writ-

ten (see Table 28, Security Code area). This area

can be accessed only in Read mode by the final

user. It is impossible to change the security num-

ber after it has been written by ST.

Table 23. Query Structure Overview

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

Table 24. CFI Query Identification String

Note: Query data are always presented on the lowest order data outputs (DQ7-DQ0) only. DQ8-DQ15 are ‘0’.

Address

Sub-section Name

Description

x16

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

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 27)

P = 40h

16h

2Ch

0000h

17h

2Eh

0000h

Alternate Vendor Command Set and Control Interface ID Code second

vendor - specified algorithm supported

18h

30h

0000h

19h

32h

0000h

Address for Alternate Algorithm extended Query table

1Ah

34h

0000h

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