HY29F002T
Table 4. Composition of Command Sequences
n In a Program command sequence, the Read/
Reset command may be written between the
sequence cycles before programming actually
begins. This aborts the command and resets
the device to the Read mode, or to the Erase
Suspend mode if the Program command se-
quence is written while the device is in the
Erase Suspend mode. Once programming
begins, however, the device ignores Read/Re-
set commands until the operation is complete.
Number of Bus Cycles
Command
Sequence
Unlock Command
Data
Read/Reset 1
Read/Reset 2
Byte Program
Chip Erase
0
2
2
4
4
0
0
2
1
1
1
1
1
1
1
1
Note 1
Note 1
1
1
Sector Erase
Erase Suspend
Erase Resume
Electronic ID
1 (Note 2)
n The Read/Reset command may be written be-
tween the cycles in an Electronic ID command
sequence to abort that command. As described
above, once in the Electronic ID mode, the
Read/ Reset command must be written to re-
turn to the Read mode.
0
0
Note 3
Notes:
1. Any number of Flash array read cycles are permitted.
2. Additional data cycles may follow. See text.
3. Any number of Electronic ID read cycles are permitted.
Byte Program Command
A Read/Reset command must be issued in order
to read array data in the following cases:
The host processor programs the device a byte at
a time by issuing the Program command sequence
shown in Table 5. The sequence begins by writ-
ing two unlock cycles, followed by the Program
setup command and, lastly, a data cycle specify-
ing the program address and data. This initiates
the Automatic Programming algorithm, which pro-
vides internally generated program pulses and
verifies the programmed cell margin. The host is
not required to provide further controls or timings
during this operation. When the Automatic Pro-
gramming algorithm is complete, the device re-
turns to the Read mode. Several methods are
provided to allow the host to determine the status
of the programming operation, as described in the
Write Operation Status section.
n If the device is in the Electronic ID mode, a
Read/ Reset command must be written to re-
turn to the Read mode. If the device was in the
Erase Suspend mode when the device entered
the Electronic ID mode, writing the Read/Re-
set command returns the device to the Erase
Suspend mode.
Note: When in the Electronic ID bus operation mode,
the device returns to the Read mode when VID is re-
moved from the A[9] pin. The Read/Reset command is
not required in this case.
n If DQ[5] (Exceeded Time Limit) goes High dur-
ing a program or erase operation, writing the
reset command returns the sectors to the Read
mode (or to the Erase Suspend mode if the
device was in Erase Suspend).
Commands written to the device during execution
of the Automatic Programming algorithm are ig-
nored. Note that a hardware reset immediately
terminates the programming operation. To en-
sure data integrity, the aborted program command
sequence should be reinitiated once the reset
operation is complete.
The Read/Reset command may also be used to
abort certain command sequences:
n In a Sector Erase or Chip Erase command se-
quence, the Read/Reset command may be
written at any time before erasing actually be-
gins, including, for the Sector Erase command,
between the cycles that specify the sectors to
be erased (see Sector Erase command de-
scription). This aborts the command and re-
sets the device to the Read mode. Once era-
sure begins, however, the device ignores Read/
Reset commands until the operation is com-
plete.
Programming is allowed in any sequence. Only
erase operations can convert a stored “0” to a “1”.
Thus, a bit cannot be programmed from a “0” back
to a “1”. Attempting to do so will set DQ[5] to “1”,
and the Data# Polling algorithm will indicate that
the operation was not successful. A Read/Reset
command or a hardware reset is required to exit
Rev. 4.1/May 01
10
HYNIX [ HYNIX SEMICONDUCTOR ]
