TH50VSF3680 Datasheet, PDF (29/55 Pages) Toshiba Semiconductor – SRAM AND FLASH MEMORY MIXED MULTI-CHIP PACKAGE

Auto Block / Multiple Block Erase Mode
TH50VSF3680/3681AASB
The Auto Block and Multiple Block Erase modes 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. To erase multiple blocks, repeat the 6^th bus
write cycles and input the block addresses and the Auto Block Erase command within the erase hold time (Auto
Multiple Block Erase). If a command sequence other than Auto Block Erase or Erase Suspend command is input
during the erase hold time, the device resets the Command register and enters Read mode. The erase hold time
is valid every WE rising edge. Once operation starts, all the memory cells in the block selected in the device are
automatically preprogrammed to data 0, erased, and Erase is verified. The device status can be determined from
the setting of the Hardware Sequence flag. To read the Hardware Sequence flag, the addresses of blocks on which
Auto Erase is being performed must be specified. When the selected blocks exit in all the banks, simultaneous
operation cannot be performed.
Commands (except Erase Suspend) are ignored during a Block/Multiple Block Erase operation. The operation
can be aborted by a hardware reset. The Auto Erase operation does not complete correctly when aborted,
therefore, a further Erase operation is necessary.
An 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 determined from the Hardware Sequence flag. Either a Reset command or a Hardware reset is
necessary to return the device to Read mode after a failure. If multiple blocks are selected, the block in which a
failure occurred cannot be detected. Either terminate device usage, or perform Block Erase for each block, specify
the failed block, and stop using it. The host processor must take measures to prevent use of the failed block being
used in the future.
Erase Suspend / Resume Mode
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. The Erase Suspend command is inhibited to input during the Erase Hold Time. 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 .
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