s29ns01gs Meet Spansion Inc., s29ns01gs Datasheet - Page 17

• Manufacturer Part Number: s29ns01gs
• Description: S29ns01gs 1024 Megabit 128 Megabyte 16-bit Data Width, Burst Access, Simultaneous Read/write, 1.8 Volt-only Flash Memory In 65 Nm Mirrorbit Technology
• Manufacturer: Meet Spansion Inc.

6.3
April 20, 2009 S29NS-S_00_02
6.3.1
6.3.2
Device ID and CFI (ID-CFI) ASO
JEDEC Device ID
Common Flash Memory Interface
There are two traditional methods for systems to identify the type of Flash memory installed in the system.
One has traditionally been called Autoselect and is now referred to as Device Identification (ID). A command
is used to enable an address space overlay where up to 16 word locations can be read to get JEDEC
manufacturer identification (ID), and device ID from the Flash memory. The system can use the manufacturer
and device IDs to select the appropriate driver software to use with the Flash device. The other method is
called Common Flash Interface (CFI). It also uses a command to enable an address space overlay where an
extendable table of standard information about how the Flash memory is organized and behaves can be
read. With this method the driver software does not have to be written with the specifics of each possible
memory device in mind. Instead the driver software is written in a more general way to handle many different
devices but adjusts the driver behavior based on the information in the CFI table stored in the Flash memory.
Traditionally these two address spaces have used separate commands and were separate overlays.
However, the mapping of these two address spaces are non-overlapping and so can be combined in to a
single address space and appear together in a single overlay. Either of the traditional commands used to
access (enter) the Autoselect (ID) or CFI overlay will cause the now combined ID-CFI address map to appear.
A write at any sector address using CAP3, with xx98h or xx90h data, switches the addressed sector to an
overlay of the ID-CFI address map. These are called ID-CFI Enter commands and are only valid when written
to a bank that is in read mode. The ID-CFI address map appears within, and replaces Flash Array data of, the
selected sector address range. The ID-CFI enter commands use the same address and data values used on
previous generation memories to access the JEDEC Manufacturer ID (Autoselect) and Common Flash
Interface (CFI) information, respectively. While the ID-CFI address space is overlaid, any write with xxF0h
data to the device will remove the overlay and return the selected sector to showing Flash memory array
data. Thus, the ID-CFI address space and commands are backward compatible with standard memory
discovery algorithms.
Within the ID-CFI address map there are two subsections:
For the complete address map see Tables in
Address Map on page
The Joint Electron Device Engineering Council (JEDEC) standard JEP106 defines a method for reading the
manufacturer ID and device ID of a compliant memory. This information is primarily intended for programming
equipment to automatically match a device with the corresponding programming algorithm.
The JEDEC ID information is structured to work with any memory data bus width e.g. x8, x16, x32. The code
values are always byte wide but are located at bus width address boundaries such that incrementing the
device address inputs will read successive byte, word, or double word locations with the codes always
located in the least significant byte location of the data bus. Because the data bus is word wide each code
byte is located in the lower half of each word location and the high order byte is always zero.
The Common Flash Interface (CFI) specification defines a standardized data structure that may be read from
a flash memory device, which allows vendor-specified software algorithms to be used for entire families of
devices. The data structure contains information for system configuration such as various electrical and
timing parameters, and special functions supported by the device. Software support can then be device-
independent, JEDEC ID-independent, and forward-and-backward-compatible for the specified flash device
families.
The system can read CFI information at the addresses within the selected sector as shown in
Device ID and Common Flash Memory Interface Address Map on page
(SA) + 00000h to 0001Fh
(SA) + 00020h to 00BEh
Byte Address
D a t a
S h e e t
69.
S29NS-S MirrorBit
Table 6.3 ID-CFI Address Map Overview
(traditional Autoselect values)
( P r e l i m i n a r y )
CFI data structure
Description
JEDEC ID
®
Eclipse
Section 11.2, Device ID and Common Flash Memory Interface
™
Flash Family
Size Allocated (Max. Bytes)
69.
480
32
Section 11.2,
Read/Write
Read Only
Read Only
17