TC58FVT641 datasheet(17/53 Pages) TOSHIBA

17 / 53 page

TC58FVT641/B641FT/XB-70,-10

2001-09-06

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DQ6 (Toggle bit 1)

The device status can be determined by the Toggle Bit function during an Auto-Program or auto-erase

operation. The Toggle bit begins toggling on the rising edge of WE in the last bus cycle. DQ6 alternately

outputs a 0 or a 1 for each OE access while CE = VIL while the device is busy. When the internal operation

has been completed, toggling stops and valid memory cell data can be read by subsequent reading. If the

operation fails, the DQ6 output toggles.

If an attempt is made to execute an Auto Program operation on a protected block, DQ6 will toggle for around

3 µs. It will then stop toggling. If an attempt is made to execute an auto erase operation on a protected block,

DQ6 will toggle for around 100 µs. It will then stop toggling. After toggling has stopped the device will return to

Read Mode.

DQ5 (internal time-out)

If the internal timer times out during a Program or Erase operation, DQ5 outputs a 1. This indicates that the

operation has not been completed within the allotted time.

Any attempt to program a 1 into a cell containing a 0 will fail (see Auto-Program Mode). In this case DQ5

outputs a 1. Either a hardware reset or a software Reset command is required to return the device to Read

Mode.

DQ3 (Block Erase timer)

The Block Erase operation starts 50 µs (the Erase Hold Time) after the rising edge of WE in the last

command cycle. DQ3 outputs a 0 for the duration of the Block Erase Hold Time and a 1 when the Block Erase

operation starts. Additional Block Erase commands can only be accepted during the Block Erase Hold Time.

Each Block Erase command input within the hold time resets the timer, allowing additional blocks to be marked

for erasing. DQ3 outputs a 1 if the Program or Erase operation fails.

DQ2 (Toggle bit 2)

DQ2 is used to indicate which blocks have been selected for Auto Block Erase or to indicate whether the

device is in Erase Suspend Mode.

If data is read continuously from the selected block during an Auto Block Erase, the DQ2 output will toggle.

Now 1 will be output from non-selected blocks; thus, the selected block can be ascertained. If data is read

continuously from the block selected for Auto Block Erase while the device is in Erase Suspend Mode, the DQ2

output will toggle. Because the DQ6 output is not toggling, it can be determined that the device is in Erase

Suspend Mode. If data is read from the address to which data is being written during Erase Suspend in

Programming Mode, DQ2 will output a 1.

(READY/

)

TC58FVT641/B641 has a

signal to indicate the device status to the host processor. A 0 (Busy state)

indicates that an Auto-Program or auto-erase operation is in progress. A 1 (Ready state) indicates that the

operation has finished and that the device can now accept a new command.

outputs a 0 when an

operation has failed.

outputs a 0 after the rising edge of WE in the last command cycle.

During an Auto Block Erase operation, commands other than Erase Suspend are ignored.

outputs a

1 during an Erase Suspend operation. The output buffer for the

pin is an open-drain type circuit,

allowing a wired-OR connection. A pull-up resistor must be inserted between VDD and the

pin.

BUSY

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