MBM29DL34TF Fujitsu Media Devices, MBM29DL34TF Datasheet - Page 35

• Manufacturer Part Number: MBM29DL34TF
• Description: (MBM29DL34BF/TF) FLASH MEMORY CMOS 32 M (4 M X 8/2 M X 16) BIT
• Manufacturer: Fujitsu Media Devices

16. DQ
Exceeded Timing Limits
17. DQ
Sector Erase Timer
18. DQ
Toggle Bit II
19. Reading Toggle Bits DQ
DQ
these conditions DQ
cycle was not successfully completed. Data Polling is the only operating function of the devices under this
condition. The CE circuit will partially power down the device under these conditions (to approximately 2 mA) .
The OE and WE pins will control the output disable functions as described in “MBM29DL34TF/BF User Bus
Operations Tables (BYTE = V
The DQ
case the devices lock out and never complete the Embedded Algorithm operation. Hence the system never
reads a valid data on DQ
DQ
If this occurs, reset the device with command sequence.
After the completion of the initial sector erase command sequence the sector erase time-out will begin. DQ
remain low until the time-out is complete. Data Polling and Toggle Bit are valid after the initial sector erase
command sequence.
If Data Polling or the Toggle Bit I indicates a valid erase command has been written, DQ
determine whether the sector erase timer window is still open. If DQ
cycle has begun. If DQ
command has been accepted, the system software should check the status of DQ
subsequent Sector Erase command. If DQ
been accepted.
See “Hardware Sequence Flags Table”.
This Toggle Bit II, along with DQ
Algorithm or in Erase Suspend.
Successive reads from the erasing sector will cause DQ
devices are in the erase-suspended-read mode, successive reads from the erase-suspended sector will cause
DQ
address of the non-erase suspended sector will indicate a logic “1” at the DQ
DQ
Program operation is in progress. The behavior of these two status bits, along with that of DQ
as follows :
For example DQ
(DQ
DIAGRAM.
Furthermore DQ
if this bit is read from an erasing sector.
To operate Toggle Bit function properly, CE or OE must be high when bank address is changed.
Whenever the system initially begins reading Toggle Bit status, it must read DQ
to determine whether a Toggle Bit is toggling. Typically a system would note and store the value of the Toggle
Bit after the first read. After the second read, the system would compare the new value of the Toggle Bit with
the first. If the Toggle Bit is not toggling, the device has completed the program or erase operation. The system
can read array data on DQ
However, after the initial two read cycles, if the system determines that the Toggle Bit is still toggling, the system
also should note whether the value of DQ
5
5
2
6
2
bit will indicate a “1.” Note that this is not a device failure condition since the devices were incorrectly used.
will indicate if the program or erase time has exceeded the specified limits (internal pulse count) . Under
to toggle. When the devices are in the erase-suspended-program mode, successive reads from the byte
5
3
2
is different from DQ
toggles while DQ
5
failure condition may also appear if a user tries to program a non blank location without erasing. In this
2
2
can also be used to determine which sector is being erased. At the erase mode, DQ
and DQ
5
will produce a “1”. This is a failure condition which indicates that the program or erase
3
6
7
is low (“0”) , the device will accept additional sector erase commands. To insure the
does not.) See also “Toggle Bit Status Table” and “9. DQ
2
6
bit and DQ
7
in that DQ
can be used together to determine if the erase-suspend-read mode is in progress.
to DQ
IH
6
/DQ
and BYTE = V
6
, can be used to determine whether the devices are in the Embedded Erase
0
2
on the following read cycle.
6
6
never stops toggling. Once the devices have exceeded timing limits, the
toggles only when the standard program or Erase, or Erase Suspend
5
3
were high on the second status check, the command may not have
is high (see “15. DQ
IL
)” (
DEVICE BUS OPERATION).
2
to toggle during the Embedded Erase Algorithm. If the
5
”) . If it is, the system should then determine
MBM29DL34TF/BF
3
is high (“1”) , the internally controlled erase
2
bit.
7
to DQ
3
prior to and following each
2
vs. DQ
0
at least twice in a row
3
6
7
” in
may be used to
, is summarized
2
TIMING
toggles
3
will
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