BOOT SECTOR FLASH
Austin Semiconductor, Inc.
COMMON FLASH MEMORY 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. 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
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 Tables 5–8. The system must
write the reset command to return the device to the
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 Tables 5–8. 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.
Table 5: CFI Query Identification String
Query Unique ASCII String "QRY"
Primary OEM Command Set
Address for Primary Extended Table
Alternate OEM Command Set (00h=none exists)
Address for Alternate OEM Extended Table (00h=none exists)
Rev. 0.0 02/09
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