
A49LF040A 
PRELIMINARY (March, 2006, Version 0.1) 
12 
AMIC Technology, Corp.
ADDRESS/ADDRESS MULTIPLEXED (A/A MUX) 
MODE
Device Operation 
Commands are used to initiate the memory operation 
functions of the device. The data portion of the software 
command sequence is latched on the rising edge of 
WE
 . 
During the software command sequence the row address is 
latched on the falling edge of 
R/
latched on the rising edge of 
Table 11 for operation modes and the command sequence. 
C
R/
 and the column address is 
C
. Refer to Table 10 and 
Read 
The Read operation of the A49LF040A device is controlled 
by OE . OE  is the output control and is used to gate data 
from the output pins. Refer to the Read cycle timing diagram, 
Figure 10 for further details. 
Reset 
A V
IL
 on RST  pin initiates a device reset. 
Byte-Program Operation 
The A49LF040A device is programmed on a byte-by-byte 
basis. Before programming, one must ensure that the block, 
in which the byte which is being programmed exists, is fully 
erased. The Byte-Program operation is initiated by executing 
a four-byte command load sequence for Software Data 
Protection with address and data in the last byte sequence. 
During the Byte-Program operation, the row address (A10-A0) 
is latched on the falling edge of 
(A18-A11) is latched on the rising edge of 
is latched in the rising edge of 
WE
 . See Figure 11 for 
Program operation timing diagram, Figure 14 for timing 
waveforms, and Figure 19 for its flowchart. During the 
Program operation, the only valid reads are 
Data
 Polling and 
Toggle Bit. During the internal Program operation, the host is 
free to perform additional tasks. Any commands written 
during the internal Program operation will be ignored. 
C
R/
 and the column Address 
C
R/
. The data bus 
Table 10: A/A Mux Mode Operation Selection
Block-Erase Operation 
The Block-Erase Operation allows the system to erase the 
device in 64 KByte uniform block size for the A49LF040A. 
The Block-Erase operation is initiated by executing a six-byte 
command load sequence for Software Data Protection with 
Block-Erase command (30H or 50H) and block address. The 
internal Block-Erase operation begins after the sixth 
WE
pulse. The End-of-Erase can be determined using either 
Data
 Polling or Toggle Bit methods. See Figure 15 for timing 
waveforms. Any commands written during the Block- Erase 
operation will be ignored. 
Chip-Erase 
The A49LF040A device provides a Chip-Erase operation 
only in A/A Mux mode, which allows the user to erase the 
entire memory array to the ‘1’s state. This is useful when the 
entire device must be quickly erased. The Chip-Erase 
operation is initiated by executing a six-byte Software Data  
Protection command sequence with Chip-Erase command 
(10H) with address 5555H in the last byte sequence. The 
internal Erase operation begins with the rising edge of the 
sixth 
WE
 .  During the internal Erase operation, the only 
valid read is Toggle Bit or 
Data
 Polling. See Table 11 for the 
command sequence, Figure 16 for timing diagram, and 
Figure 21 for the flowchart. Any commands written during the 
Chip-Erase operation will be ignored. 
Write Operation Status Detection 
The A49LF040A device provides two software means to 
detect the completion of a Write cycle, in order to optimize 
the system Write cycle time. The software detection includes 
two status bits: 
Data
 Polling (I/O
7
) and Toggle Bit (I/O
6
). The 
End-of-Write detection mode is enabled after the rising edge 
of 
WE
  which initiates the internal Write operation. The 
actual completion of the nonvolatile write is asynchronous 
with the system; therefore, either a 
Data
  Polling or Toggle 
Bit read may be simultaneous with the completion of the 
Write cycle.  
Mode 
RST
OE
WE
Address 
I/O 
Read 
V
IH
V
IH
V
IH
V
IH
V
IL
V
IL
V
IH
V
IH
V
IH
X 
V
IH
V
IL
V
IH
X 
A
IN
A
IN
X 
D
OUT
D
IN
High Z 
Write 
Standby 
Output Disable 
X 
High Z 
Reset 
X 
X 
High Z 
A18 – A2 = X, A1 = V
IL
, A0 = V
IL
A18 – A2 = X, A1 = V
IL
, A0 = V
IH
Manufacturer ID 
Device ID 
Product Identification 
V
IH
V
IL
V
IH
A18 – A2 = X, A1 = V
IH
, A0 = V
IH
Continuation ID