Features
•
•
•
•
Single-voltage Read/Write Operation: 2.7V to 3.6V (BV), 3.0V to 3.6V (LV)
Fast Read Access Time – 70 ns
Internal Erase/Program Control
Sector Architecture
– One 8K Word (16K Bytes) Boot Block with Programming Lockout
– Two 4K Word (8K Bytes) Parameter Blocks
– One 240K Word (480K Bytes) Main Memory Array Block
Fast Sector Erase Time – 10 Seconds
Byte-by-byte or Word-by-word Programming – 30 µs Typical
Hardware Data Protection
Data Polling for End of Program Detection
Low Power Dissipation
– 25 mA Active Current
– 50 µA CMOS Standby Current
Typical 10,000 Write Cycles
•
•
•
•
•
•
Description
The AT49BV/LV4096A is a 3-volt, 4-megabit Flash memory organized as 524,288
words of 8 bits each or 256K words of 16 bits each. Manufactured with Atmel’s
advanced nonvolatile CMOS technology, the device offers access times to 70 ns with
power dissipation of just 67 mV at 2.7V read. When deselected, the CMOS standby
current is less than 50 µA.
The device contains a user-enabled “boot block” protection feature. The
AT49BV/LV4096A locates the boot block at lowest order addresses (“bottom boot”).
To allow for simple in-system reprogrammability, the AT49BV/LV4096A does not
require high input voltages for programming. Reading data out of the device is similar
to reading from an EPROM; it has standard CE, OE and WE inputs to avoid bus con-
tention. Reprogramming the AT49BV/LV4096A is performed by first erasing a block of
data and then programming on a byte-by-byte or word-by-word basis.
4-megabit
(512K x 8/
256K x 16)
Single 2.7-volt
Battery-Voltage
™
Flash Memory
AT49BV4096A
AT49LV4096A
Pin Configurations
Pin Name
A0 - A17
CE
OE
WE
RESET
VPP
I/O0 - I/O15
I/O15(A-1)
BYTE
NC
Function
Addresses
Chip Enable
Output Enable
Write Enable
Reset
VPP can be left unconnected or connected to VCC, GND, 5V or
12V. The input has no effect on the operation of the device.
Data Inputs/Outputs
I/O15 (Data Input/Output, Word Mode)
A-1 (LSB Address Input, Byte Mode)
Selects Byte or Word Mode
No Connect
Rev. 1618H–FLASH–4/04
1
AT49BV/LV4096A SOIC (SOP)
VPP
NC
A17
A7
A6
A5
A4
A3
A2
A1
A0
CE
GND
OE
I/O0
I/O8
I/O1
I/O9
I/O2
I/O10
I/O3
I/O11
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
RESET
WE
A8
A9
A10
A11
A12
A13
A14
A15
A16
BYTE
GND
I/O15/A-1
I/O7
I/O14
I/O6
I/O13
I/O5
I/O12
I/O4
VCC
AT49BV/LV4096A TSOP Top View
Type 1
A15
A14
A13
A12
A11
A10
A9
A8
NC
NC
WE
RESET
VPP
NC
NC
NC
A17
A7
A6
A5
A4
A3
A2
A1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
A16
BYTE
GND
I/O15/A-1
I/O7
I/O14
I/O6
I/O13
I/O5
I/O12
I/O4
VCC
I/O11
I/O3
I/O10
I/O2
I/O9
I/O1
I/O8
I/O0
OE
GND
CE
A0
The device is erased by executing the Erase command sequence; the device internally
controls the erase operation. The memory is divided into four blocks for erase opera-
tions. There are two 4K word parameter block sections, the boot block, and the main
memory array block. The typical number of program and erase cycles is in excess of
10,000 cycles.
The 8K word boot block section includes a reprogramming lock out feature to provide
data integrity. This feature is enabled by a command sequence. Once the boot block
programming lockout feature is enabled, the data in the boot block cannot be changed
when input levels of 5.5 volts or less are used. The boot sector is designed to contain
user secure code.
The BYTE pin controls whether the device data I/O pins operate in the byte or word
configuration. If the BYTE pin is set at a logic “1” or left open, the device is in word con-
figuration, I/O0 - I/O15 are active and controlled by CE and OE.
If the BYTE pin is set at logic “0”, the device is in byte configuration, and only data I/O
pins I/O0 - I/O7 are active and controlled by CE and OE. The data I/O pins I/O8 - I/O14
are tri-stated and the I/O15 pin is used as an input for the LSB (A-1) address function.
2
AT49BV/LV4096A
1618H–FLASH–4/04
AT49BV/LV4096A
Block Diagram
VCC
GND
OE
WE
CE
RESET
ADDRESS
INPUTS
INPUT/OUTPUT
BUFFERS
PROGRAM DATA
LATCHES
Y-GATING
MAIN MEMORY
(240K WORDS)
PARAMETER
BLOCK 2
4K WORDS
PARAMETER
BLOCK 1
4K WORDS
BOOT BLOCK
8K WORDS
DATA INPUTS/OUTPUTS
I/O0 - I/O15
CONTROL
LOGIC
Y DECODER
X DECODER
3FFFF
04000
03FFF
03000
02FFF
02000
01FFF
00000
Device Operation
READ:
The AT49BV/LV4096A 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.
COMMAND SEQUENCES:
When the device is first powered on, it will be reset to the
read or standby mode, depending upon the state of the control line inputs. In order to
perform other device functions, a series of command sequences are entered into the
device. The command sequences are shown in the Command Definitions table (I/O8 -
I/O15 are don’t care inputs for the command codes). The command sequences are writ-
ten 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. Standard microprocessor write
timings are used. The address locations used in the command sequences are not
affected by entering the command sequences.
RESET:
A RESET input pin is provided to ease some system applications. When
RESET is at a logic high level, the device is in its standard operating mode. A low level
on the RESET input halts the present device operation and puts the outputs of the
device in a high-impedance state. When a high level is reasserted on the RESET pin,
the device returns to the read or standby mode, depending upon the state of the control
inputs. By applying a 12V ± 0.5V input signal to the RESET pin, the boot block array can
be reprogrammed even if the boot block program lockout feature has been enabled (see
“Boot Block Programming Lockout Override” section).
ERASURE:
Before a byte or word can be reprogrammed, it must be erased. The erased
state of memory bits is a logic “1”. The entire device can be erased by using the Chip
Erase command or individual sectors can be erased by using the Sector Erase
commands.
3
1618H–FLASH–4/04
CHIP ERASE:
The entire device can be erased at one time by using the 6-byte chip
erase software code. After the chip erase has been initiated, the device will internally
time the erase operation so that no external clocks are required. The maximum time to
erase the chip is t
EC
.
If the boot block lockout has been enabled, the chip erase will not erase the data in the
boot block; it will erase the main memory block and the parameter blocks only. After the
chip erase, the device will return to the read or standby mode.
SECTOR ERASE:
As an alternative to a full chip erase, the device is organized into four
sectors that can be individually erased. There are two 4K word parameter block sec-
tions, one boot block, and the main memory array block. The Sector Erase command is
a six-bus cycle operation. The sector address is latched on the falling WE edge of the
sixth cycle while the 30H data input command is latched at the rising edge of WE. The
sector erase starts after the rising edge of WE of the sixth cycle. The erase operation is
internally controlled; it will automatically time to completion. Whenever the main memory
block is erased and reprogrammed, the two parameter blocks should be erased and
reprogrammed before the main memory block is erased again. Whenever a parameter
block is erased and reprogrammed, the other parameter block should be erased and
reprogrammed before the first parameter block is erased again. Whenever the boot
block is erased and reprogrammed, the main memory block and the parameter blocks
should be erased and reprogrammed before the boot block is erased again.
BYTE/WORD PROGRAMMING:
Once a memory block is erased, it is programmed (to
a logic “0”) on a byte-by-byte or word-by-word basis. Programming is accomplished via
the internal device command register and is a four-bus cycle operation. The device will
automatically generate the required internal program pulses.
Any commands written to the chip during the embedded programming cycle will be
ignored. If a hardware reset happens during programming, the data at the location being
programmed will be corrupted. Please note that a data “0” cannot be programmed back
to a “1”; only erase operations can convert “0”s to “1”s. Programming is completed after
the specified t
BP
cycle time. The Data Polling feature may also be used to indicate the
end of a program cycle.
BOOT BLOCK PROGRAMMING LOCKOUT:
The device has one designated block
that has a programming lockout feature. This feature prevents programming of data in
the designated block once the feature has been enabled. The size of the block is 8K
words. This block, referred to as the boot block, can contain secure code that is used to
bring up the system. Enabling the lockout feature will allow the boot code to stay in the
device while data in the rest of the device is updated. This feature does not have to be
activated; the boot block’s usage as a write-protected region is optional to the user. The
address range of the boot block is 00000H to 01FFFH.
Once the feature is enabled, the data in the boot block can no longer be erased or pro-
grammed when input levels of 5.5V or less are used. Data in the main memory block
can still be changed through the regular programming method. To activate the lockout
feature, a series of six program commands to specific addresses with specific data must
be performed. Please refer to the Command Definitions table.
BOOT BLOCK LOCKOUT DETECTION:
A software method is available to determine if
programming of the boot block section is locked out. When the device is in the software
product identification mode (see Software Product Identification Entry and Exit sections)
a read from the following address location will show if programming the boot block is
locked out – 00002H. If the data on I/O0 is low, the boot block can be programmed; if
the data on I/O0 is high, the program lockout feature has been enabled and the block
4
AT49BV/LV4096A
1618H–FLASH–4/04
AT49BV/LV4096A
cannot be programmed. The software product identification exit code should be used to
return to standard operation.
BOOT BLOCK PROGRAMMING LOCKOUT OVERRIDE:
The user can override the
boot block programming lockout by taking the RESET pin to 12 volts during the entire
chip erase, sector erase or word programming operation. When the RESET pin is
brought back to TTL levels, the boot block programming lockout feature is again active.
PRODUCT IDENTIFICATION:
The product identification mode identifies the device and
manufacturer as Atmel. It may be accessed by hardware or software operation. The
hardware operation mode can be used by an external programmer to identify the correct
programming algorithm for the Atmel product.
For details, see “Operating Modes” (for hardware operation) or “Software Product Identi-
fication Entry/Exit” on page 12. The manufacturer and device codes are the same for
both modes.
DATA POLLING:
The AT49BV/LV4096A 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. During a chip
or sector erase operation, an attempt to read the device will give a “0” on I/O7. Once the
program or erase cycle has completed, true data will be read from the device. Data Poll-
ing may begin at any time during the program cycle.
TOGGLE BIT:
In addition to Data Polling, the AT49BV/LV4096A 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 pro-
gram cycle.
HARDWARE DATA PROTECTION:
Hardware features protect against inadvertent pro-
grams to the AT49BV/LV4096A 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)
before 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 2.7V to 3.6V power supply, the address and
control inputs (OE, CE and WE) may be driven from 0 to 5.5V without adversely affect-
ing the operation of the device. The I/O lines can only be driven from 0 to V
CC
+ 0.6V.
5
1618H–FLASH–4/04
