3.6 Read Identifier Codes
The read-identifier codes operation outputs the
manufacturer code, device code, and block lock
configuration codes for each block configuration
(see Figure 5). Using the manufacturer and
device codes, the system software can
automatically match the device with its proper
algorithms. The block-lock configuration codes
identify each block’s lock-bit setting.
Figure 5. Device Identifier Code Memory Map
Writing commands to the CUI enables reading of
device data, query, identifier codes, inspection
and clearing of the Status Register. Additionally,
when VPP = VPPH, block erasure, programming,
and lock-bit configuration can also be performed.
The Block Erase command requires appropriate
command data and an address within the block
to be erased. The Byte/Word Write command
requires the command and address of the
location to be written. Set Block Lock-Bit
commands require the command and address
within the block to be locked. The Clear Block
Lock-Bits command requires the command and
an address within the device.
The CUI does not occupy an addressable
memory location. It is written when WE#, CE0#,
and CE1# are active and OE# = VIH. The address
and data needed to execute a command are
latched on the rising edge of WE# or CEX#
(CE0#, CE1#), whichever goes high first.
Standard microprocessor write timings are used.
Figure 17 illustrates a write operation.
4.0 COMMAND DEFINITIONS
VPP voltage ≤ VPPLK enables read operations
from the Status Register, identifier codes, or
memory blocks. Placing VPPH on VPP enables
successful block erase, programming, and lock-
bit configuration operations.
Device operations are selected by writing specific
commands into the CUI. Table 2 and Table 3
define these commands.
12 ADVANCE INFORMATION