TH50VSF3680 Datasheet, PDF (31/55 Pages) Toshiba Semiconductor – SRAM AND FLASH MEMORY MIXED MULTI-CHIP PACKAGE

Hidden Rom Area
TH50VSF3680/3681AASB
The TH50VSF3680/3681AASB features a 64-Kbyte Hidden ROM area apart from the memory cells. The area
consists of one block. Data Read, Write, and Protect can be performed on the block. Because Protect cannot be
released, once the block is protected, data in the block cannot be overwritten.
The Hidden ROM area is located in the address space indicated in the Hidden ROM Area Address Table.
Normally, memory cell data are accessed. To access the Hidden ROM area, input a Hidden ROM mode Entry
command. At this time, the device enters Hidden ROM mode, allowing Read, Write, Erase, and Block Protect.
Write and Erase operations are the same as Auto operations except that the device is in Hidden ROM mode. To
protect the Hidden ROM area, use the Block Protect function. Operation of Block Protect here is the same as in
normal Block Protect except that VIH rather than VID is input to RESET . Once the block is protected,
protection cannot be released even using a Temporary Block Unprotect function. Use Block Protect carefully.
Note that in Hidden ROM mode, simultaneous operation cannot be performed. Therefore, do not access areas
other than the Hidden ROM area.
To exit Hidden ROM mode, use the Hidden ROM Mode Exit command. The device returns to Read mode.
Hidden Rom Area Address Table
TYPE
BOOT BLOCK
ARCHITECTURE
BYTE MODE
ADDRESS RANGE
SIZE
TH50VSF3680AASB TOP BOOT BLOCK 7F0000H~7FFFFFH 64 Kbytes
TH50VSF3681AASB BOTTOM BOOT BLOCK 000000H~00FFFFH 64 Kbytes
WORD MODE
ADDRESS RANGE
SIZE
3F8000H~3FFFFFH 32 Kwords
000000H~007FFFH 32 Kwords
2001-03-06 31/55