TH50VSF3583AASB Datasheet, PDF (25/50 Pages) Toshiba Semiconductor – TOSHIBA MULTI-CHIP INTEGRATED CIRCUIT SILICON GATE CMOS

Block Protect
TH50VSF3582/3583AASB
Block Protection is a function to disable write and erase in block units.
Applying VID to RESET and inputting the Block Protect command performs block protection. The first cycle of
the command sequence is the Setup command. In the second cycle, the Block Protect command is input, in
which a block address and A1 = VIH and A0 = A6 = VIL are input. At this time, the device writes to the block
protector circuit, Until write is complete, there must be a wait of tPPLH but the device need not be controlled
during this time. In the third cycle, the Verify Block Protect command is input. This command verifies write to
the block protector circuit. Read is performed in the fourth cycle. If the protection operation is complete, 01H is
output. If other than 01H is output, write is not complete; thus, input the Block Protect command again.
Canceling VID to RESET exits this mode.
Temporary Block Unprotection
The TC58VSF3580/3581AASB has a temporary block unprotection feature which disables block protection for
all protected blocks. Unprotection is enabled by applying VID to the RESET pin. At this time, Write and Erase
operations can be performed on all the blocks except the boot blocks protected by Boot Block Protect. The device
returns to the previous condition after VID is removed from the RESET pin. That is, previously protected
blocks are protected again.
Verify Block Protect
The Verify Block Protect command is used to ascertain whether a block is protected or unprotected. This mode
is set by setting A0, A6 and the block address A19~A12 to VIL and setting A1 to VIH. This command should be
input before a Read operation is performed. 0001H is output if the block is protected and 0000H is output if the
block is unprotected. In Byte Mode DQ8 to DQ15 are in High-Impedance state. Block protection verification can
also be carried out using a software command.
Boot Block Protection
Boot Block Protection temporarily protects some boot blocks using a method other than ordinary block
protection. VID or a command sequence is not required. Protection is performed simply by inputting VIL to
WP/ACC . The target blocks are two of the boot blocks. The Top Boot Block uses BA69/BA70; the Bottom Boot
Block, BA0/BA1. Inputting VIH to WP/ACC releases the mode. At this time, the block is protected in ordinary
block protection mode.
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