
A49FL004
PRELIMINARY       (September, 2005, Version 0.0) 
16 
AMIC Technology, Corp.
through four consecutive memory write cycles. In A/A Mux 
mode, a program operation is activated by writing the three-
byte command sequence and program address/data through 
four consecutive bus cycles.  
The row address (A10 - A0) is latched on the falling edge of 
C
R/
and the column address (A21 - A11) is latched on the 
rising edge of 
of WE . Once the program operation is started, the internal 
control logic automatically handles the internal programming 
voltages and timing.  
C
R/
. The data is latched on the rising edge 
A data “0” can not be programmed back to a “1”. Only erase 
operation can convert “0”s to “1”s. The 
Data
 Polling on I/O
7
or Toggle Bit on I/O
6
 can be used to detect when the 
programming operation is completed in FWH, LPC, and A/A 
Mux modes. 
Data
  Polling (I/O
7
) 
The device provides a 
Data
  Polling feature to indicate the 
progress or the completion of a program or erase operation 
in all modes. During a program operation, an attempt to read 
the device will result in the complement of the last loaded 
data on I/O
7
. Once the program cycle is complete, the true 
data of the last loaded data is valid on all outputs. During an 
erase operation, an attempt to read the device will result a 
“0” on I/O
7
. After the erase cycle is complete, an attempt to 
read the device will result a “1” on I/O
7
. 
Toggle Bit (I/O
6
) 
The A49FL004 also provides a Toggle Bit feature to detect 
the progress or the completion of a program or erase 
operation. During a program or erase operation, an attempt 
to read data from the devices will result in I/O
6
 toggling 
between “1” and “0”. When the program or erase operation is 
complete, I/O
6
 will stop toggling and valid data will be read. 
Toggle bit may be accessed at any time during a program or 
erase operation. 
Data Protection 
The device features a software data protection function to 
protect the device from an unintentional erase or program 
operation. It is performed by JEDEC standard Software Data 
Protection (SDP) command sequences. See Table 14 for 
SDP Command Definition. A program operation is initiated by 
three memory write cycles of unlock command sequence.  
A chip (only available in A/A Mux mode), sector or block 
erase operation is initiated by six memory write cycles of 
unlock 
command 
sequence. 
sequence, any invalid command or sequence will abort the 
operation and force the device back to standby mode. 
Memory Hardware Write Protection 
The A49FL004 has a 64 KByte top boot block. When working 
in-system, the memory hardware write protection feature can 
be activated by two control pins - Top Block Lock (
TBL
 ) and 
Write Protection ( WP ) for both FWH and LPC modes. When 
TBL
 is pulled low (V
IL
), the boot block is hardware write 
protected. A sector erase, block erase, or byte program 
command attempts to erase or program the boot block will be 
ignored. When WP is pulled low (V
IL
), the Block 0 ~ Block 6 
of A49FL004 (except the boot block) are hardware write 
During 
SDP 
command 
protected. Any attempt to erase or program a sector or block 
within this area will be ignored.  
Both 
TBL
  and WP  pins must be set low (V
IL
) for protection 
or high (V
IH
) for un-protection prior to a program or erase 
operation. A logic level change on 
TBL
  or WP  pin during a 
program or erase operation may cause unpredictable results. 
The
 TBL
 and WP  pins work in combination with the block 
locking registers. When active, these pins write protect the 
appropriate blocks regardless of the associated block locking 
registers setting. 
Hardware Data Protection 
Hardware data protection protects the devices from 
unintentional erase or program operation. It is performed by 
the device automatically in the following three ways:  
(a) V
DD
 Detection: if V
DD
 is below 1.8 V (typical), the program 
and erase functions are inhibited. 
(b) Write Inhibit Mode: holding any of the signal 
OE
  low, or 
WE  high inhibits a write cycle (A/A Mux mode only). 
(c) Noise/Glitch Protection: pulses of less than 5 ns (typical) 
on the WE  input will not initiate a write cycle (A/A Mux mode 
only). 
Reset 
Any read, program, or erase operation to the devices can be 
reset by the INIT or RST  pins. INIT and RST  pins are 
internally hard-wired and have same function to the devices. 
The INIT pin is only available in FWH and LPC modes. The 
RST  pin is available in all modes. It is required to drive 
INIT or RST  pins low during system reset to ensure proper 
initialization.  
During a memory read operation, pulls low the INIT or 
RST
pin will reset the devices back to standby mode and then the 
FWH[3:0] of FWH interface or the LAD[3:0] of LPC interface 
will go to high impedance state. During a program or erase 
operation, pulls low the INIT or 
RST
 pin will abort the 
program or erase operation and reset the devices back to 
standby mode. A reset latency will occur before the devices 
resume to standby mode when such reset is performed. 
When a program or erase operation is reset before the 
completion of such operation, the memory contents of 
devices may become invalid due to an incomplete program 
or erase operation. 
Product Identification 
The product identification mode can be used to read the 
Manufacturer ID and the Device ID by a software Product ID 
Entry command in both in-system hardware interface and 
A/A Mux interface modes. The product identification mode is 
activated by three-bus-cycle command. Refer to Table 12 for 
the Manufacturer ID and Device ID of A49FL004 and Table 
14 for the SDP Command Definition.  
In FWH mode, the product identification can also be read 
directly at FFBC0000h for Manufacturer ID - “99h” and 
FFBC0001h for Device ID in the 4 GByte system memory 
map.