TH50VSF2582 Datasheet, PDF (24/50 Pages) Toshiba Semiconductor – SRAM AND FLASH MEMORY MIXED MULTI-CHIP PACKAGE

Auto Block Erase / Auto Multi-Block Erase Modes
TH50VSF2582/2583AASB
The Auto Block Erase Mode and Auto Multi-Block Erase Mode are set using the Block Erase command. The
block address is latched on the falling edge of the WE signal in the sixth bus cycle. The block erase starts as
soon as the Erase Hold Time (tBEH) has elapsed after the rising edge of the WE signal. When multiple blocks
are erased, the sixth Bus Write cycle is repeated with each block address and Auto Block Erase command being
input within the Erase Hold Time (this constitutes an Auto Multi-Block Erase operation). If a command other
than an Auto Block Erase command or Erase Suspend command is input during the Erase Hold Time, the
device will reset the Command Register and enter Read Mode. The Erase Hold Time restarts on each successive
rising edge of WE . Once operation starts, all memory cells in the selected block are automatically
preprogrammed to 0, erased and verified as erased by the chip. The device status is indicated by the setting of
the Hardware Sequence flag. When the Hardware Sequence flag is read, the addresses of the blocks on which
auto-erase operation is being performed must be specified. If the selected blocks are spread across all nine
banks, simultaneous operation cannot be carried out.
All commands (except Erase Suspend) are ignored during an Auto Block Erase or Auto Multi-Block Erase
operation. Either operation can be aborted using a Hardware Reset. If an auto-erase operation is interrupted, it
cannot be completed correctly; therefore, a further erase operation is necessary to complete the erasing.
Any attempt to erase a protected block is ignored. If all the selected blocks are protected, the auto-erase
operation is not executed and the device returns to Read Mode 100 µs after the rising edge of the WE signal in
the last bus cycle.
If an auto-erase operation fails, the device remains in Erasing state and does not return to Read Mode. The
device status is indicated by the Hardware Sequence flag. After a failure either a Reset command or a Hardware
Reset is required to return the device to Read Mode. If multiple blocks are selected, it will not be possible to
ascertain the block in which the failure occurred. In this case either abandon use of the device altogether, or
perform a Block Erase on each block, identify the failed block, and stop using it. The host processor must take
measures to prevent subsequent use of the failed block.
Erase Suspend / Erase Resume Modes
Erase Suspend Mode suspends Auto Block Erase and reads data from or writes data to an unselected block.
The Erase Suspend command is allowed during an auto block erase operation but is ignored in all other
oreration modes. When the command is input, the address of the bank on which Erase is being performed must
be specified.
In Erase Suspend Mode only a Read, Program or Resume command can be accepted. If an Erase Suspend
command is input during an Auto Block Erase, the device will enter Erase Suspend Read Mode after tSUSE. The
device status (Erase Suspend Read Mode) can be verified by checking the Hardware Sequence flag. If data is
read consecutively from the block selected for Auto Block Erase, the DQ2 output will toggle and the DQ6 output
will stop toggling and RY/BY will be set to High-Impedance.
Inputting a Write command during an Erase Suspend enables a Write to be performed to a block which has
not been selected for the Auto Block Erase. Data is written in the usual manner.
To resume the Auto Block Erase, input an Erase Resume command. On input of the command, the address of
the bank on which the Write was being performed must be specified. On receiving an Erase Resume command,
the device returns to the state it was in when the Erase Suspend command was input. If an Erase Suspend
command is input during the Erase Hold Time, the device will return to the state it was in at the start of the
Erase Hold Time. At this time more blocks can be specified for erasing. If an Erase Resume command is input
during an Auto Block Erase, Erase resumes. At this time toggle output of DQ6 resumes and 0 is output on
RY/BY .
2001-10-25 24/50