JS28F256J3A-150 datasheet(52/72 Pages) INTEL

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256-Mbit J3 (x8/x16)

Datasheet

Appendix A Common Flash Interface

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. This allows device independent, JEDEC ID-independent, and forward-

and backward-compatible software support for the specified flash device families. It allows flash

vendors to standardize their existing interfaces for long-term compatibility.

This appendix defines the data structure or “database” returned by the Common Flash Interface

(CFI) Query command. System software should parse this structure to gain critical information

such as block size, density, x8/x16, and electrical specifications. Once this information has been

obtained, the software will know which command sets to use to enable flash writes, block erases,

and otherwise control the flash component. The Query command is part of an overall specification

for multiple command set and control interface descriptions called Common Flash Interface, or

CFI.

A.1

Query Structure Output

The Query “database” allows system software to gain information for controlling the flash

component. This section describes the device’s CFI-compliant interface that allows the host system

to access Query data.

Query data are always presented on the lowest-order data outputs (D[7:0]) only. The numerical

offset value is the address relative to the maximum bus width supported by the device. On this

family of devices, the Query table device starting address is a 10h, which is a word address for x16

devices.

For a word-wide (x16) device, the first two bytes of the Query structure, “Q” and “R” in ASCII,

appear on the low byte at word addresses 10h and 11h. This CFI-compliant device outputs 00H

data on upper bytes. Thus, the device outputs ASCII “Q” in the low byte (D[7:0]) and 0x00 (00h)

in the high byte (D[15:8]).

At Query addresses containing two or more bytes of information, the least significant data byte is

presented at the lower address, and the most significant data byte is presented at the higher address.

In all of the following tables, addresses and data are represented in hexadecimal notation, so the

“h” suffix has been dropped. In addition, since the upper byte of word-wide devices is always

“00h,” the leading “00” has been dropped from the table notation and only the lower byte value is

shown. Any x16 device outputs can be assumed to have 00h on the upper byte in this mode.

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