NAND512-A2C データシートの表示（PDF） - Numonyx -> Micron
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NAND512-A2C Datasheet PDF : 51 Pages
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NAND512-A2C
6
Device operations
Device operations
6.1
Pointer operations
As the NAND Flash memories contain two different areas for x16 devices and three different
areas for x8 devices (see Figure 6) the read command codes (00h, 01h, 50h) are used to
act as pointers to the different areas of the memory array (they select the most significant
column address).
The Read A and Read B commands act as pointers to the main memory area. Their use
depends on the bus width of the device.
● In x16 devices the Read A command (00h) sets the pointer to Area A (the whole of the
main area) that is Words 0 to 255.
● In x8 devices the Read A command (00h) sets the pointer to Area A (the first half of the
main area) that is Bytes 0 to 255, and the Read B command (01h) sets the pointer to
Area B (the second half of the main area) that is Bytes 256 to 511.
In both the x8 and x16 devices the Read C command (50h), acts as a pointer to Area C (the
spare memory area) that is Bytes 512 to 527 or Words 256 to 263.
Once the Read A and Read C commands have been issued the pointer remains in the
respective areas until another pointer code is issued. However, the Read B command is
effective for only one operation, once an operation has been executed in Area B the pointer
returns automatically to Area A.
The pointer operations can also be used before a program operation, that is the appropriate
code (00h, 01h or 50h) can be issued before the program command 80h is issued (see
Figure 7).
Figure 6. Pointer operations
x8 Devices
Area A
(00h)
Area B
(01h)
Area C
(50h)
Bytes 0- 255
Bytes 256-511
Bytes 512
-527
x16 Devices
Area A
(00h)
Words 0- 255
Area C
(50h)
Words 256
-263
A
B
C Page Buffer
Pointer
(00h,01h,50h)
A
C Page Buffer
Pointer
(00h,50h)
AI07592
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