Preliminary
K5A3x80YT(B)C
MCP MEMORY
Unlock Bypass
Flash memory provides the unlock bypass mode to save its program time. The mode is invoked by the unlock bypass command
sequence. Unlike the standard program command sequence that contains four bus cycles, the unlock bypass program command
sequence comprises only two bus cycles.
The unlock bypass mode is engaged by issuing the unlock bypass command sequence which is comprised of three bus cycles. Writ-
ing first two unlock cycles is followed by a third cycle containing the unlock bypass command (20H). Once the device is in the unlock
bypass mode, the unlock bypass program command sequence is necessary to program in this mode. The unlock bypass program
command sequence is comprised of only two bus cycles; writing the unlock bypass program command (A0H) is followed by the pro-
gram address and data. This command sequence is the only valid one for programming the device in the unlock bypass mode.
The unlock bypass reset command sequence is the only valid command sequence to exit the unlock bypass mode. The unlock
bypass reset command sequence consists of two bus cycles. The first cycle must contain the data (90H). The second cycle contains
only the data (00H). Then, the device returns to the read mode
Chip Erase
To erase a chip is to write 1¢s into the entire memory array by executing the Internal Erase Routine. The Chip Erase requires six bus
cycles to write the command sequence. The erase set-up command is written after first two "unlock" cycles. Then, there are two
more write cycles prior to writing the chip erase command. The Internal Erase Routine automatically pre-programs and verifies the
entire memory for an all zero data pattern prior to erasing. The automatic erase begins on the rising edge of the last WE or CE
F
pulse in the command sequence and terminates when DQ7 is "1". After that the device returns to the read mode.
WE
A20~A0(x16)/
A20~A-1(x8)
555H/
AAAH
2AAH/
555H
555H/
AAAH
555H
AAAH
2AAH/
555H
555H/
AAAH
80H
55H
AAH
AAH
55H
10H
DQ15-DQ0
RY/BY
Chip Erase
Start
Figure 5. Chip Erase Command Sequence
Block Erase
To erase a block is to write 1¢s into the desired memory block by executing the Internal Erase Routine. The Block Erase requires six
bus cycles to write the command sequence shown in Table 5. After the first two "unlock" cycles, the erase setup command (80H) is
written at the third cycle. Then there are two more "unlock" cycles followed by the Block Erase command. The Internal Erase Routine
automatically pre-programs and verifies the entire memory prior to erasing it. The block address is latched on the falling edge of WE
or CE , while the Block Erase command is latched on the rising edge of WE or CE .
F
F
Multiple blocks can be erased sequentially by writing the six bus-cycle operation in Fig 6. Upon completion of the last cycle for the
Block Erase, additional block address and the Block Erase command (30H) can be written to perform the Multi-Block Erase. An 50us
(typical) "time window" is required between the Block Erase command writes. The Block Erase command must be written within the
50us "time window", otherwise the Block Erase command will be ignored. The 50us "time window" is reset when the falling edge of
the WE occurs within the 50us of "time window" to latch the Block Erase command. During the 50us of "time window", any command
other than the Block Erase or the Erase Suspend command written to the device will reset the device to read mode. After the 50 us
of "time window", the Block Erase command will initiate the Internal Erase Routine to erase the selected blocks. Any Block Erase
address and command following the exceeded "time window" may or may not be accepted. No other commands will be recognized
except the Erase Suspend command.
Revision 0.0
November 2002
- 13 -
SAMSUNG [ SAMSUNG ]
