
Retired Product
DS05-20907-4E_July 31, 2007
MBM29PL32TM/BM90/10
36
DQ5
Exceeded Timing Limits
DQ5 will indicate if the program or erase time has exceeded the specified limits (internal pulse count). Under
these conditions DQ5 will produce a “1”. This is a failure condition indicating that the program or erase cycle was
not successfully completed. Data Polling is the only operating function of the device 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 “MBM29PL32TM/BM User Bus Operations (Word
Mode : BYTE = VIH)” and “MBM29PL32TM/BM User Bus Operations (Byte Mode : BYTE = VIL)” in
■DEVICE
BUS OPERATION.
The DQ5 failure condition may also appear if a user tries to program a non blank location without pre-erase. In
this case the device locks out and never completes the Embedded Algorithm operation. Hence, the system never
reads a valid data on DQ7 bit and DQ6 never stop toggling. Once the device has exceeded timing limits, the DQ5
bit will indicate a “1”. Note that this is not a device failure condition since the device was incorrectly used. If this
occurs, reset the device with command sequence.
DQ3
Sector Erase Timer
After the completion of the initial sector erase command sequence the sector erase time-out will begin. DQ3 will
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, DQ3 may be used to
determine whether the sector erase timer window is still open. If DQ3 is “1” the internally controlled erase cycle
has begun. If DQ3 is “0”, the device will accept additional sector erase commands. To insure the command has
been accepted, the system software should check the status of DQ3 prior to and following each subsequent
Sector Erase command. If DQ3 were high on the second status check, the command may not have been accepted.
See “Hardware Sequence Flags”.
DQ2
Toggle Bit II
This Toggle bit II, along with DQ6, can be used to determine whether the devices are in the Embedded Erase
Algorithm or in Erase Suspend.
Successive reads from the erasing sector will cause DQ2 to toggle during the Embedded Erase Algorithm. If the
devices are in the erase-suspended-read mode, successive reads from the erase-suspended sector will cause
DQ2 to toggle. When the device is in the erase-suspended-program mode, successive reads from the non-erase
suspended sector will indicate a logic “1” at the DQ2 bit.
DQ6 is different from DQ2 in that DQ6 toggles only when the standard program or Erase, or Erase Suspend
Program operation is in progress. The behavior of these two status bits, along with that of DQ7, is summarized
as follows:
For example, DQ2 and DQ6 can be used together to determine if the erase-suspend-read mode is in progress.
(DQ2 toggles while DQ6 does not.) See also “Hardware Sequence Flags” and “DQ2 vs. DQ6” in
■SWITCHING
WAVEFORM.
Furthermore, DQ2 can also be used to determine which sector is being erased. At the erase mode, DQ2 toggles
if this bit is read from an erasing sector.