TMS29LF800T Datasheet, PDF (15/49 Pages) Texas Instruments – Array-Blocking Architecture

TMS29LF800T, TMS29LF800B
1048576 BY 8-BIT/524288 BY 16-BIT
FLASH MEMORIES
SMJS828B – SEPTEMBER 1996 – REVISED OCTOBER 1997
sector-erase command (continued)
One to nineteen sector-address locations can be loaded in any sequence. The state of the delay timer can be
monitored using the sector-erase delay indicator (DQ3). If DQ3 is at logic low, the time delay has not expired.
See the operation status section for a description.
Any command other than erase suspend (B0h) or sector erase (30h) written to the device during the
sector-erase operation causes the device to exit the sector-erase mode and the contents of the sector(s)
selected for erase are no longer valid. To complete the sector-erase operation, reissue the sector-erase
command sequence.
The embedded sector-erase function automatically provides needed voltage and timing to program and to verify
all of the memory cells prior to electrical erase and then erases and verifies the cell margin automatically.
Programming the memory cells prior to erase is not required.
See the operation status section for a full description. Figure 14 shows a flowchart of the typical sector-erase
operation.
erase-suspend command
The erase-suspend command (B0h) allows interruption of a sector-erase operation to read data from unaltered
sectors of the device. Erase-suspend is a one-bus-cycle command. The addresses can be V_IL or V_IH and the
erase-suspend command (B0h) is latched on the rising edge of WE. Once the sector-erase operation is in
progress, the erase-suspend command requests the internal write-state machine to halt operation at
predetermined breakpoints. The erase-suspend command is valid only during the sector-erase operation and
is invalid during programming and chip-erase operations. The sector-erase delay timer expires immediately if
the erase-suspend command is issued while the delay is active.
After the erase-suspend command is issued, the device takes between 0.1 µs and 15 µs to suspend the
operation. The toggle bit must be monitored to determine when the suspend has been executed. When the
toggle bit stops toggling, data can be read from sectors that are not selected for erase. Reading from a sector
selected for erase can result in invalid data. See the operation status section for a full description.
Once the sector-erase operation is suspended, reading from or programing to a sector that is not being erased
can be performed. This command is applicable only during sector-erase operation. Any other command written
during erase-suspend mode to the suspended sector is ignored.
erase-resume command
The erase-resume command (30h) restarts a suspended sector-erase operation from the point where it was
halted. Erase resume is a one-bus-cycle command. The addresses can be V_IL or V_IH and the erase-resume
command (30h) is latched on the rising edge of WE. When an erase-suspend/erase-resume command
combination is written, the internal-pulse counter (exceed timing limit) is reset. The erase-resume command
is valid only in the erase-suspend state. After the erase-resume command is executed, the device returns to
the valid sector-erase state and further writes of the erase-resume command are ignored. After the device has
resumed the sector-erase operation, another erase-suspend command can be issued to the device.
operation status
The status of the device during an automatic-programming algorithm, chip-erase, or automatic-erase algorithm
can be determined in three ways:
D DQ7: Data polling
D DQ6: Toggle bit
D RY/BY: Ready/busy bit
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