
ABSOLUTE MAXIMUM RATINGS* 
A49LF004 
PRELIMINARY      (November, 2003, Version 0.0) 
5 
AMIC Technology, Corp.
Temperature Under Bias  . . . . . . . . . .  . . . -55
°
C to + 125
°
C 
Storage Temperature . . . . . . . . . . . . . . . . . -65
°
C to + 125
°
C 
D.C. Voltage on Any Pins with Respect to Ground 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to VDD + 0.5V 
Package Power Dissipation Capability (Ta=25
°
C) 
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to VDD + 0.5V 
Output Short Circuit Current 
. . . . .  . . . . . . . . . . .    50mA
Notes: 
1. Minimum DC voltage on input or I/O pins is -0.5V. During 
voltage transitions, input or I/O pins may undershoot VSS to -
2.0V for periods of up to 20ns. Maximum DC voltage on input 
and I/O pins is VDD + 0.5V. During voltage transitions, input or 
I/O pins may
overshoot to VDD + 2.0V for periods up to 20ns. 
2. No more than one output is shorted at a time. Duration of the 
short circuit should not be greater than one second. 
*Comments
Stresses above those listed under "Absolute Maximum Ratings" 
may cause permanent damage to this device. These are stress 
ratings only. Functional operation of this device at these or any 
other conditions above those indicated in the operational sections of 
these specifications are not implied or intended. Exposure to the 
absolute maximum rating conditions for extended periods may 
affect device reliability. 
Operating Ranges 
Commercial (C) Devices 
Ambient Temperature (T
A
) . . . . . . . . . . . . . . 0
°
C to +85
°
C 
VDD Supply Voltages 
VDD for all devices  . . . . . . . . . . . . . . . . . . +3.0V to +3.6V 
Operating ranges define those limits between which the 
functionally of the device is guaranteed. 
MODE SELECTION 
The A49LF004 flash memory devices can operate in two 
distinct interface modes: the Firmware Hub Interface 
(FWH) mode and the Address/Address Multiplexed (A/A 
Mux) mode. The IC (Interface Configuration pin) is used to 
set the interface mode selection. If the IC pin is set to logic 
High, the device is in A/A Mux mode; while if the IC pin is set 
Low, the device is in the FWH mode. The IC selection pin 
must be configured prior to device operation. The IC pin is 
internally pulled down if the pin is not connected. In FWH 
mode, the device is configured to interface with its host 
using 
Intel’s 
Firmware 
Hub 
Communication between Host and the A49LF004 occurs via 
the 4-bit I/O communication signals, FWH [3:0] and the 
FWH4. In A/A Mux mode, the device is programmed via an 
11-bit address A
10
-A
0
 and an 8-bit data I/O
7
-I/O
0
 parallel 
signals. The address inputs are multiplexed in row and 
column selected by control signal R/C# pin. The column 
addresses are mapped to the higher internal addresses, and 
the row addresses are mapped to the lower internal 
addresses. See the Device Memory Maps in Figure 3 for 
address assignment. 
proprietary 
protocol. 
FWH MODE OPERATION 
The FWH interface consists of four data signals (FWH[3:0]), 
one control signal (FWH4) and a clock (CLK). The data 
signals, control signal and clock comply with PCI 
specifications. Operations such as Memory Read and 
Memory Write use Intel FWH propriety protocol. JEDEC 
Standard SDP (Software Data Protection) Byte-Program and 
Block-Erase command sequences are incorporated into the 
FWH memory cycles. Chip-Erase command is only available 
in A/A Mux mode. The addresses and data are transferred 
through FWH[3:0] synchronized with the input clock CLK 
during a FWH memory cycle. The pulse of FWH4 is inserted 
for at least one clock period to indicate the start of a FWH 
memory cycle. The address or data on FWH[3:0] is latched 
on the rising edge of CLK. The device enters standby mode 
when FWH4 is high and no internal operation is in progress. 
The device is in ready mode when FWH4 is low and no 
activity is on the FWH bus. 
FWH Read Operation 
FWH Read operations read from the memory cells or 
specific registers in the FWH device. A valid FWH Read 
operation starts when FWH4 is Low as CLK rises and a 
START value “1101b” is on FWH[3:0]. Addresses and data 
are transferred to and from the device decided by a series of 
“fields”. Field sequences and contents are strictly defined for 
FWH Read operations. Refer to Table 2 for FWH Read 
Cycle Definition. 
FWH Write Operation 
FWH Write operations write to the FWH Interface or FWH 
registers. A valid FWH Write operation starts when FWH4 is 
Low as CLK rises and a START value “1110b” is on 
FWH[3:0]. Addresses and data are transferred to and from 
the device decided by a series of “fields”. Field sequences 
and contents are strictly defined for FWH Write operations. 
Refer to Table 3 for FWH write Cycle Definition. 
FWH Abort Operation 
If FWH4 is driven low for one or more clock cycles during a 
FWH cycle, the cycle will be terminated and the device will 
wait for the ABORT command. The host may drive the 
FWH[3:0] with ‘1111b’ (ABORT command) to return the 
device to Ready mode. If abort occurs during a Write 
operation, the data may be incorrectly altered. 
Response To Invalid Fields 
During FWH operations, the FWH will not explicitly indicate 
that it has received invalid field sequences. The response to 
specific invalid fields or sequences is as follows: 
Address out of range: 
The FWH address sequence is 7 
fields long (28 bits), but only the last five address fields 
(20 bits) will be decoded by A49LF004. Address A22 has the 
special function of directing reads and writes to the flash 
memory (A22=1) or to the register space (A22=0).