Read CFI Query command
The Read CFI Query Command is used to read data from the Common Flash Interface
(CFI) memory Area. This command is valid when the device is in the Read Array mode, or
when the device is in Auto Select mode.
One Bus Write cycle is required to issue the Read CFI Query Command. Once the
command is issued subsequent Bus Read operations read from the Common Flash
Interface memory Area.
The Read/Reset command must be issued to return the device to the previous mode (the
Read Array mode or Auto Select mode). A second Read/Reset command would be needed
if the device is to be put in the Read Array mode from Auto Select mode.
See Appendix B: Common Flash Interface (CFI), Table 22, Table 23, Table 24, Table 25,
Table 26 and Table 27 for details on the information contained in the Common Flash
Interface (CFI) memory area.
The Program command can be used to program a value to one address in the memory array
at a time. The command requires four Bus Write operations, the final write operation latches
the address and data, and starts the Program/Erase Controller.
If the address falls in a protected block then the Program command is ignored, the data
remains unchanged. The Status register is never read and no error condition is given.
During the program operation the memory will ignore all commands. It is not possible to
issue any command to abort or pause the operation. After programming has started, Bus
Read operations output the Status register content. See Section 5: Status register for more
details. Typical program times are given in Table 6
After the program operation has completed the memory will return to the Read mode, unless
an error has occurred. When an error occurs Bus Read operations will continue to output
the Status register. A Read/Reset command must be issued to reset the error condition and
return to Read mode.
Note that the Program command cannot change a bit set at ’0’ back to ’1’. One of the Erase
Commands must be used to set all the bits in a block or in the whole memory from ’0’ to ’1’.