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Advanced+ Boot Block Flash Memory (C3)
58 Datasheet
Appendix C Common Flash Interface
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 is part of an overall specification for
multiple command set and control interface descriptions called Common Flash Interface, or CFI.
C.1 Query Structure Output
The Query database allows system software to obtain information for controlling the flash device.
This section describes the device’s CFI-compliant interface that allows access to Query data.
Query data are presented on the lowest-order data outputs (DQ0-DQ7) 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 0x10, which is a word address for x16 devices.
For a word-wide (x16) device, the first two Query-structure bytes, ASCII “Q” and “R,” appear on
the low byte at word addresses 0x10 and 0x11. This CFI-compliant device outputs 0x00 data on
upper bytes. The device outputs ASCII “Q” in the low byte (DQ0-DQ7) and 0x00 in the high byte
(DQ8-DQ15).
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
“0x00,” 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 0x00 on the upper byte in this mode.
Table 24. Summary of Query Structure Output as a Function of Device and Mode
Device Hex Offset Hex Code ASCII Value
Device Addresses
00010: 51 "Q"
00011: 52 "R"
00012: 59 "Y"
Table 25. Example of Query Structure Output of x16 Devices (Sheet 1 of 2)
Word Addressing:
Offset Hex Code Value
A[X-0] DQ[16:0]
0x00010 0051 "Q"
0x00011 0052 "R"
0x00012 0059 "Y"
0x00013 P_IDLO PrVendor
