Document Number: 002-00870 Rev.*K

Page 21 of 56

S29AS008J

9.

Common Flash Memory Interface (CFI)

The Common Flash Interface (CFI) specification outlines device and host system software interrogation handshake, which allows

specific vendor-specified software algorithms to be used for entire families of devices. Software support can then be device-

independent, JEDEC ID-independent, and forward- and backward-compatible for the specified flash device families. Flash vendors

can standardize their existing interfaces for long-term compatibility.

This device enters the CFI Query mode when the system writes the CFI Query command, 98h, to address 55h in word mode (or

address AAh in byte mode), any time the device is ready to read array data. The system can read CFI information at the addresses

given in Table to Table on page 23. In word mode, the upper address bits (A7–MSB) must be all zeros. To terminate reading CFI

data, the system must write the reset command.

The system can also write the CFI query command when the device is in the autoselect mode. The device enters the CFI query

mode, and the system can read CFI data at the addresses given in Table to Table on page 23. The system must write the reset

command to return the device to the autoselect mode.

For further information, please refer to the CFI Specification and CFI Publication 100, available via the World Wide Web at http://

www.amd.com/products/nvd/overview/cfi.html. Alternatively, contact a Cypress representative for copies of these documents.

CFI Query Identification String

Addresses

(Word Mode)

Addresses

(Byte Mode)

Data

Description

10h

11h

12h

20h

22h

24h

0051h

0052h

0059h

Query Unique ASCII string “QRY”

13h

14h

26h

28h

0002h

0000h

Primary OEM Command Set

15h

16h

2Ah

2Ch

0040h

0000h

Address for Primary Extended Table

17h

18h

2Eh

30h

0000h

0000h

Alternate OEM Command Set (00h = none exists)

19h

1Ah

32h

34h

0000h

0000h

Address for Alternate OEM Extended Table (00h = none exists)