MBM29F080A datasheet(19/47 Pages) FUJITSU

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MBM29F080A-55/-70/-90

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 I are valid after the initial sector erase

command sequence.

If Data Polling or the Toggle Bit I indicates the device has been written with a valid erase command, DQ3 may

be used to determine if the sector erase timer window is still open. If DQ3 is high (“1”) the internally controlled

erase cycle has begun; attempts to write subsequent commands (other than Erase Suspend) to the device will

be ignored until the erase operation is completed as indicated by Data Polling or Toggle Bit I. If DQ3 is low (“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.

Refer to Table 7: Hardware Sequence Flags.

DQ2

Toggle Bit II

This toggle bit II, along with DQ6, can be used to determine whether the device is 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 device is 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 byte

address of the non-erase suspended sector will indicate a logic “1” at the DQ2 bit.

Notes: 1. These status flags apply when outputs are read from a sector that has been erase-suspended.

2. These status flags apply when outputs are read from the byte address of the non-erase suspended sector.

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 the erase-suspend-read mode (DQ2 toggles while

DQ6 does not). See also Table 7 and Figure 15.

Furthermore, DQ2 can also be used to determine which sector is being erased. When the device is in the erase

mode, DQ2 toggles if this bit is read from the erasing sector.

Mode

DQ7

DQ6

DQ2

Program

DQ7

toggles

Erase

toggles

Erase Suspend Read (1)

(Erase-Suspended Sector)

toggles

Erase Suspend Program

DQ7 (2)

toggles

1 (2)

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