W28V400B/T
Read Identifier Codes Operation
The read identifier codes operation outputs the manufacturer code and device code (refer to Figure 4).
Using the manufacturer and device codes, the system CPU can automatically match the device with
its proper algorithms.
[A17-A0]
3FFFF
Reserved for
Future Implementation
00002
Device Code
00001
00000
Manufacture Code
Figure 4. Device Identifier Code Memory Map
Write
Writing commands to the CUI enable reading of device data and identifier codes. They also control
inspection and clearing of the status register. When VDD = VDD1/2/3/4 and used. VPP = VPPH1/2/3, the CUI
additionally controls block erasure and word/byte write.
The Block Erase command requires appropriate command data and an address within the block to be
erased. The Word/Byte Write command requires the command and address of the location to be
written.
The CUI does not occupy an addressable memory location. A write occurs when #WE and #CE are
active (low). The address and data needed to execute a command are latched on the rising edge of
#WE or #CE, whichever occurs first. Standard microprocessor write timings are used.
Figures 15 and 16 illustrate #WE and #CE controlled write operations.
9. COMMAND DEFINITIONS
When VPP ≤ VPPLK, read operations from the status register, identifier codes, or blocks are enabled.
Setting VPPH1/2/3 = VPP enables successful block erase and word/byte write operations.
Device operations are selected by writing specific commands into the CUI. Table 4 defines these
commands.
Publication Release Date: April 11, 2003
- 11 -
Revision A4
WINBOND [ WINBOND ]
