AT29LV040A
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
Single Voltage, Range 3V to 3.6V Supply
3-Volt-Only Read and Write Operation
Software Protected Programming
Fast Read Access Time - 200 ns
Low Power Dissipation
15 mA Active Current
20
µA
CMOS Standby Current
Sector Program Operation
Single Cycle Reprogram (Erase and Program)
2048 Sectors (256 bytes/sector)
Internal Address and Data Latches for 256-Bytes
Two 16 KB Boot Blocks with Lockout
Fast Sector Program Cycle Time - 20 ms Max.
Internal Program Control and Timer
DATA Polling for End of Program Detection
Typical Endurance > 10,000 Cycles
CMOS and TTL Compatible Inputs and Outputs
Commercial and Industrial Temperature Ranges
Description
The AT29LV040A is a 3-volt-only in-system Flash Programmable and Erasable Read
Only Memory (PEROM). Its 4 megabits of memory is organized as 524,288 words by
8 bits. Manufactured with Atmel’s advanced nonvolatile CMOS EEPROM technology,
the device offers access times up to 200 ns, and a low 54 mW power dissipation.
When the device is deselected, the CMOS standby current is less than 20
µA.
The
device endurance is such that any sector can typically be written to in excess of
10,000 times. The programming algorithm is compatible with other devices in Atmel’s
3-volt-only Flash memories.
To allow for simple in-system reprogrammability, the AT29LV040A does not require
high input voltages for programming. Three-volt-only commands determine the opera-
tion of the device. Reading data out of the device is similar to reading from an EPROM.
Reprogramming the AT29LV040A is performed on a sector basis; 256-bytes of data
are loaded into the device and then simultaneously programmed.
During a reprogram cycle, the address locations and 256-bytes of data are captured
at microprocessor speed and internally latched, freeing the address and data bus for
other operations. Following the initiation of a program cycle, the device will automat-
ically erase the sector and then program the latched data using an internal control
timer. The end of a program cycle can be detected by DATA polling of I/O7. Once the
end of a program cycle has been detected, a new access for a read or program can
begin.
TSOP Top View
4 Megabit
(512K x 8)
3-volt Only
256 Byte Sector
CMOS Flash
Memory
AT29LV040A
Pin Configurations
Pin Name
A0 - A18
CE
OE
WE
Function
Addresses
Chip Enable
Output Enable
Write Enable
Type 1
I/O0 - I/O7 Data Inputs/Outputs
NC
No Connect
0334C
4-83
Block Diagram
Device Operation
READ:
The AT29LV040A is accessed like an EPROM.
When CE and OE are low and WE is high, the data stored
at the memory location determined by the address pins is
asserted on the outputs. The outputs are put in the high
impedance state whenever CE or OE is high. This dual-
line control gives designers flexibility in preventing bus
contention.
SOFTWARE DATA PROTECTION PROGRAMMING:
The AT29LV040A has 2048 individual sectors, each 256-
bytes. Using the software data protection feature, byte
loads are used to enter the 256-bytes of a sector to be
programmed. The AT29LV040A can only be programmed
or reprogrammed using the software data protection fea-
ture. The device is programmed on a sector basis. If a byte
of data within the sector is to be changed, data for the en-
tire 256-byte sector must be loaded into the device. The
AT29LV040A automatically does a sector erase prior to
loading the data into the sector. An erase command is not
required.
Software data protection protects the device from inadver-
tent programming. A series of three program commands
to specific addresses with specific data must be presented
to the device before programming may occur. The same
three program commands must begin each program op-
eration. All software program commands must obey the
sector program timing specifications. Power transitions
will not reset the software data protection feature, however
the software feature will guard against inadvertent pro-
gram cycles during power transitions.
Any attempt to write to the device without the 3-byte com-
mand sequence will start the internal write timers. No data
will be written to the device; however, for the duration of
t
WC
, a read operation will effectively be a polling operation.
After the software data protection’s 3-byte command code
is given, a byte load is performed by applying a low pulse
on the WE or CE input with CE or WE low (respectively)
and OE high. The address is latched on the falling edge of
CE or WE, whichever occurs last. The data is latched by
the first rising edge of CE or WE.
The 256-bytes of data must be loaded into each sector.
Any byte that is not loaded during the programming of its
sector will be erased to read FFH. Once the bytes of a
sector are loaded into the device, they are simultaneously
programmed during the internal programming period. Af-
ter the first data byte has been loaded into the device, suc-
cessive bytes are entered in the same manner. Each new
byte to be programmed must have its high to low transition
on WE (or CE) within 150
µs
of the low to high transition of
WE (or CE) of the preceding byte. If a high to low transition
is not detected within 150
µs
of the last low to high transi-
tion, the load period will end and the internal programming
period will start. A8 to A18 specify the sector address. The
sector address must be valid during each high to low tran-
sition of WE (or CE). A0 to A7 specify the byte address
within the sector. The bytes may be loaded in any order;
sequential loading is not required. Once a programming
operation has been initiated, and for the duration of t
WC
, a
read operation will effectively be a polling operation.
HARDWARE DATA PROTECTION:
Hardware features
protect against inadvertent programs to the AT29LV040A
in the following ways: (a) V
CC
sense— if V
CC
is below 1.8V
(typical), the program function is inhibited. (b) V
CC
power
on delay— once V
CC
has reached the V
CC
sense level,
the device will automatically time out 10 ms (typical) be-
fore programming. (c) Program inhibit— holding any one
of OE low, CE high or WE high inhibits program cycles. (d)
Noise filter— pulses of less than 15 ns (typical) on the WE
or CE inputs will not initiate a program cycle.
INPUT LEVELS:
While operating with a 3.3V
±10%
power supply, the address inputs and control inputs (OE,
CE and WE) may be driven from 0 to 5.5V without ad-
versely affecting the operation of the device. The I/O lines
can only be driven from 0 to 3.6V.
(continued)
4-84
AT29LV040A
AT29LV040A
Device Operation
(Continued)
PRODUCT IDENTIFICATION:
The product identifica-
tion mode identifies the device and manufacturer as At-
mel. It may be accessed by hardware or software opera-
tion. The hardware operation mode can be used by an ex-
ternal programmer to identify the correct programming al-
gorithm for the Atmel product. In addition, users may wish
to use the software product identification mode to identify
the part (i.e. using the device code), and have the system
software use the appropriate sector size for program op-
erations. In this manner, the user can have a common
board design for 256K to 4-megabit densities and, with
each density’s sector size in a memory map, have the sys-
tem software apply the appropriate sector size.
For details, see Operating Modes (for hardware operation)
or Software Product Identification. The manufacturer and
device code is the same for both modes.
DATA POLLING:
The AT29LV040A features DATA
polling to indicate the end of a program cycle. During a
program cycle an attempted read of the last byte loaded
will result in the complement of the loaded data on I/O7.
Once the program cycle has been completed, true data is
valid on all outputs and the next cycle may begin. DATA
polling may begin at any time during the program cycle.
TOGGLE BIT:
I n a d d i t i o n t o DATA p o l l i n g t h e
AT29LV040A provides another method for determining
the end of a program or erase cycle. During a program or
erase operation, successive attempts to read data from
the device will result in I/O6 toggling between one and
zero. Once the program cycle has completed, I/O6 will
stop toggling and valid data will be read. Examining the
toggle bit may begin at any time during a program cycle.
OPTIONAL CHIP ERASE MODE:
The entire device
can be erased by using a 6-byte software code. Please
see Software Chip Erase application note for details.
BOOT BLOCK PROGRAMMING LOCKOUT:
The
AT29LV040A has two designated memory blocks that
have a programming lockout feature. This feature pre-
vents programming of data in the designated block once
the feature has been enabled. Each of these blocks con-
sists of 16K bytes; the programming lockout feature can
be set independently for either block. While the lockout
feature does not have to be activated, it can be activated
for either or both blocks.
These two 16K memory sections are referred to as
boot
blocks.
Secure code which will bring up a system can be
contained in a boot block. The AT29LV040A blocks are
located in the first 16K bytes of memory and the last 16K
bytes of memory. The boot block programming lockout
feature can therefore support systems that boot from the
lower addresses of memory or the higher addresses.
Once the programming lockout feature has been acti-
vated, the data in that block can no longer be erased or
programmed; data in other memory locations can still be
changed through the regular programming methods. To
activate the lockout feature, a series of seven program
commands to specific addresses with specific data must
be performed. Please see Boot Block Lockout Feature En-
able Algorithm.
If the boot block lockout feature has been activated on
either block, the chip erase function will be disabled.
BOOT BLOCK LOCKOUT DETECTION:
A software
method is available to determine whether programming of
either boot block section is locked out. See Software Prod-
uct Identification Entry and Exit sections. When the device
is in the software product identification mode, a read from
location 00002H will show if programming the lower ad-
dress boot block is locked out while reading location
FFFF2H will do so for the upper boot block. If the data is
FE, the corresponding block can be programmed; if the
data is FF, the program lockout feature has been activated
and the corresponding block cannot be programmed. The
software product identification exit mode should be used
to return to standard operation.
Absolute Maximum Ratings*
Temperature Under Bias................. -55°C to +125°C
Storage Temperature...................... -65°C to +150°C
All Input Voltages
(including NC Pins)
with Respect to Ground ................... -0.6V to +6.25V
All Output Voltages
with Respect to Ground .............-0.6V to V
CC
+ 0.6V
Voltage on A9
(including NC Pins)
with Respect to Ground ................... -0.6V to +13.5V
*NOTICE: Stresses beyond those listed under “Absolute Maxi-
mum Ratings” may cause permanent damage to the device.
This is a stress rating only and functional operation of the
device at these or any other conditions beyond those indi-
cated in the operational sections of this specification is not
implied. Exposure to absolute maximum rating conditions
for extended periods may affect device reliability.
4-85
DC and AC Operating Range
AT29LV040A-20
Operating
Temperature (Case)
V
CC
Power Supply
(1)
AT29LV040A-25
0°C - 70°C
-40°C - 85°C
3.3V
±
0.3V
Com.
Ind.
0°C - 70°C
-40°C - 85°C
3.3V
±
0.3V
1. After power is applied and V
CC
is at the minimum specified data sheet value, the sytem should wait 20 ms before an operational
mode is started.
Operating Modes
Mode
Read
Program
(2)
Standby/Write Inhibit
Program Inhibit
Program Inhibit
Output Disable
Product Identification
Hardware
Software
(5)
Notes: 1. X can be V
IL
or V
IH
.
2. Refer to AC Programming Waveforms.
3. V
H
= 12.0V
±
0.5V.
CE
V
IL
V
IL
V
IH
X
X
X
OE
V
IL
V
IH
X
(1)
X
V
IL
V
IH
WE
V
IH
V
IL
X
V
IH
X
X
Ai
Ai
Ai
X
I/O
D
OUT
D
IN
High Z
High Z
A1 - A18 = V
IL
, A9 = V
H (3)
,
A0 = V
IL
A1 - A18 = V
IL
, A9 = V
H (3)
,
A0 = V
IH
A0 = V
I
A0 = V
IH
Manufacturer Code
(4)
Device Code
(4)
Manufacturer Code
(4)
Device Code
(4)
V
IL
V
IL
V
IH
4. Manufacturer Code: 1F, Device Code: C4.
5. See details under Software Product Identification Entry/Exit.
DC Characteristics
Symbol
I
LI
I
LO
I
SB1
I
SB2
I
CC
V
IL
V
IH
V
OL
V
OH
Parameter
Input Load Current
Output Leakage Current
V
CC
Standby Current CMOS
V
CC
Standby Current TTL
V
CC
Active Current
Input Low Voltage
Input High Voltage
Output Low Voltage
Output High Voltage
I
OL
= 1.6 mA; V
CC
= 3.0V
I
OH
= -100
µA;
V
CC
= 3.0V
2.4
2.0
.45
Condition
V
IN
= 0V to V
CC
V
I/O
= 0V to V
CC
CE = V
CC
- 0.3V to V
CC
CE = 2.0V to V
CC
f = 5 MHz; I
OUT
= 0 mA; V
CC
= 3.6V
Com.
Ind.
Min
Max
1
1
20
50
1
15
0.6
Units
µA
µA
µA
µA
mA
mA
V
V
V
V
4-86
AT29LV040A
AT29LV040A
AC Read Characteristics
AT29LV040A-20
Symbol
t
ACC
t
CE (1)
t
OE (2)
t
DF (3, 4)
t
OH
Parameter
Address to Output Delay
CE to Output Delay
OE to Output Delay
CE or OE to Output Float
Output Hold from OE, CE or Address,
whichever occurred first
0
0
0
Min
Max
AT29LV040A-25
Min
Max
Units
ns
ns
ns
ns
ns
200
200
100
50
0
0
0
250
250
120
60
AC Read Waveforms
(1, 2, 3, 4)
Notes: 1. CE may be delayed up to t
ACC
- t
CE
after the address
transition without impact on t
ACC
.
2. OE may be delayed up to t
CE
- t
OE
after the falling
edge of CE without impact on t
CE
or by t
ACC
- t
OE
after an address change without impact on t
ACC
.
3. t
DF
is specified from OE or CE whichever occurs first
(C
L
= 5 pF).
4. This parameter is characterized and is not 100% tested.
Input Test Waveforms and Measurement Level
Output Test Load
t
R
, t
F
< 5 ns
Pin Capacitance
(f = 1 MHz, T = 25°C)
(1)
Typ
C
IN
C
OUT
Note:
Max
6
12
Units
pF
pF
Conditions
V
IN
= 0V
V
OUT
= 0V
4
8
1. These parameters are characterized and not 100% tested.
4-87
京公网安备 11010802033920号
EEWORLD
