Device operations
NAND02G-B2D
6.15
Read ONFI signature
To recognize NAND flash devices that are compatible with the ONFI 1.0 command set, the
Read Electronic Signature command can be issued, followed by an address of 20h. The
next four bytes output is the ONFI signature, which is the ASCII encoding of the ‘ONFI’ word.
Reading beyond four bytes produces indeterminate values. The device remains in this state
until a new command is issued.
Figure 32 provides a description of the read ONFI signature waveform and Table 18
provides the definition of the output bytes.
Table 18. Read ONFI signature
Value
ASCII character
1st byte
2nd byte
3rd byte
4th byte
5th byte
4Fh
4Eh
O
N
46h
F
49h
I
Undefined
Undefined
6.16
Read parameter page
The Read Parameter Page command retrieves the data structure that describes the NAND
flash organization, features, timings and other behavioral parameters. This data structure
enables the host processor to automatically recognize the NAND flash configuration of a
device. The whole data structure is repeated at least five times.
See Figure 39 for a description of the read parameter page waveform.
The Random Data Read command can be issued during execution of the read parameter
page to read specific portions of the parameter page.
The Read Status command may be used to check the status of read parameter page during
execution. After completion of the Read Status command, 00h is issued by the host on the
command line to continue with the data output flow for the Read Parameter Page command.
Read status enhanced is not be used during execution of the Read Parameter Page
command.
Table 19 defines the parameter page data structure. For parameters that span multiple
bytes, the least significant byte of the parameter corresponds to the first byte.
Values are reported in the parameter page in bytes when referring to items related to the
size of data access (as in an x 8 data access device). For example, the chip returns how
many data bytes are in a page. For a device that supports x 16 data access, the host is
required to convert byte values to word values for its use. Unused fields are set to 0h.
For more detailed information about parameter page data bits, refer to ONFI Specification
1.0 section 5.4.1.
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NUMONYX [ NUMONYX B.V ]
