Features
•
Single Voltage Operation
•
•
•
– 5V Read
– 5V Reprogramming
Fast Read Access Time - 70 ns
Internal Erase/Program Control
Sector Architecture
– One 8K Words (16K bytes) Boot Block with Programming Lockout
– Two 8K Words (16K bytes) Parameter Blocks
– One 104K Words (208K bytes) Main Memory Array Block
Fast Sector Erase Time - 10 seconds
Word-By-Word Programming - 50
µs/Word
Hardware Data Protection
DATA Polling For End Of Program Detection
Low Power Dissipation
– 50 mA Active Current
– 300
µA
CMOS Standby Current
Typical 10,000 Write Cycles
•
•
•
•
•
•
Description
The AT49F2048 is a 5-volt-only, 2 megabit Flash Memory organized as 128K 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 275 mW. When
deselected, the CMOS standby current is less than 300
µA.
To allow for simple in-system reprogrammability, the AT49F2048 does not require
high input voltages for programming. Five-volt-only commands determine the read
and programming operation of the device. Reading data out of the device is similar to
2-Megabit
(128K x 16)
5-volt Only
CMOS Flash
Memory
AT49F2048
(continued)
Pin Configurations
Pin Name
A0 - A16
CE
OE
WE
RESET
I/O0 - I/O15
NC
Function
Addresses
Chip Enable
Output Enable
Write Enable
Reset
Data
Inputs/Outputs
No Connect
TSOP Top View
Type 1
SOIC (SOP)
0568D-A–9/97
1
reading from an EPROM; it has standard CE, OE, and WE
inputs to avoid bus connection. The AT49F2048 is a 5-volt-
only, 2 megabit Flash Memory organized as 128K words
contention. Reprogramming the AT49F2048 is performed
by first erasing a block of data and then programming on a
word-by-word basis.
The device is erased by executing the erase command
sequence; the device internally controls the erase opera-
tion. The memory is divided into three blocks for erase
operations. There are two 8K word parameter block sec-
tions and one sector consisting of the boot block and the
main memory array block. The AT49F2048 is programmed
on a word-by-word basis.
The device has the capability to protect the data in the boot
block; 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 typical
number of program and erase cycles is in excess of 10,000
cycles.
The optional 8K word boot block section includes a repro-
gramming lock out feature to provide data integrity. The
boot sector is designed to contain user secure code, and
when the feature is enabled, the boot sector is protected
from being reprogrammed.
Block Diagram
Device Operation
READ:
The AT49F2048 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 conten-
tion.
COMMAND SEQUENCES:
When the device is first pow-
ered 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 written by applying a low
pulse on the WE or CE input with CE or WE low (respec-
tively) 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 loca-
2
tions used in the command sequences are not affected by
entering the command sequences.
RESET:
A RESET input pin is provided to ease some sys-
tem 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 repro-
grammed even if the boot block program lockout feature
has been enabled (see Boot Block Programming Lockout
Override section).
ERASURE:
Before a word can be reprogrammed, it must
be erased. The erased state of the memory bits is a logical
“1”. The entire device can be erased at one time by using a
6-byte software code.
AT49F2048
AT49F2048
After the software chip erase has been initiated, the device
will internally time the erase operation so that no external
clocks are required. The maximum time needed to erase
the whole chip is t
EC
.
CHIP ERASE:
If the boot block lockout has been enabled,
the Chip Erase function is disabled; sector erases for the
parameter blocks and main memory block will still operate.
After the full chip erase the device will return back to read
mode. Any command during chip erase will be ignored.
SECTOR ERASE:
As an alternative to a full chip erase,
the device is organized into three sectors that can be indi-
vidually erased. There are two 8K word parameter block
sections and one sector consisting of the 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. When the boot block pro-
gramming lockout feature is not enabled, the boot block
and the main memory block will erase together (from the
same sector erase command). Once the boot region has
been protected, only the main memory array sector will
erase when its sector erase command is issued.
WORD PROGRAMMING:
Once a memory block is
erased, it is programmed (to a logical “0”) on a word-by-
word basis. Programming is accomplished via the internal
device command register and is a 4 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 hap-
pens 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 tBP 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 acti-
vated; 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 programmed 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 soft-
ware product identification mode (see Software Product
Identification Entry and Exit sections) a read from address
location 00002H will show if programming the boot block is
locked out. If the data on I/O0 is low, the boot block can be
programmed; if the data on I/O0 is high, the program lock-
out feature has been enabled and the block cannot be pro-
grammed. The software product identification exit code
should be used to return to standard operation.
BOOT BLOCK PROGRAMMING LOCKOUT OVER-
RIDE:
The user can override the boot block programming
lockout by taking the RESET pin to 12 volts. By doing this
protected boot block data can be altered through a chip
erase, sector erase or word programming. 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 pro-
grammer to identify the correct programming algorithm for
the Atmel product.
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 AT49F2048 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 pro-
gram cycle has been completed, true data is valid on all
outputs and the next cycle may begin. During a chip or sec-
tor erase operation, an attempt to read the device will give
a “0” on I/O7. Once the program or erase cycle has com-
pleted, true data will be read from the device. DATA polling
may begin at any time during the program cycle.
TOGGLE BIT:
In addition to DATA polling the AT49F2048
provides another method for determining the end of a pro-
gram 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.
HARDWARE DATA PROTECTION:
Hardware features
protect against inadvertent programs to the AT49F2048 in
the following ways: (a) V
CC
sense: if V
CC
is below 3.8V
3
(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.
Command Definition (in Hex)
(1)
Command
Sequence
Read
Chip Erase
Sector Erase
Word Program
Boot Block
Lockout
(2)
Product ID
Entry
Product ID
Exit
(3)
Product ID
Exit
(3)
Notes:
Bus
Cycles
1
6
6
4
6
3
3
1
1st Bus
Cycle
Addr
Addr
5555
5555
5555
5555
5555
5555
xxxx
Data
D
OUT
AA
AA
AA
AA
AA
AA
F0
2AAA
2AAA
2AAA
2AAA
2AAA
2AAA
55
55
55
55
55
55
5555
5555
5555
5555
5555
5555
80
80
A0
80
90
F0
5555
5555
Addr
5555
AA
AA
D
IN
AA
2AAA
55
5555
40
2AAA
2AAA
55
55
5555
SA
(4)(5)
10
30
2nd Bus
Cycle
Addr
Data
3rd Bus
Cycle
Addr
Data
4th Bus
Cycle
Addr
Data
5th Bus
Cycle
Addr
Data
6th Bus
Cycle
Addr
Data
1. The DATA FORMAT in each bus cycle is as follows: I/O15 - I/O8 (Don't Care); I/O7 - I/O0 (Hex)
2. The 8K word boot sector has the address range 00000H to 01FFFH.
3. Either one of the Product ID Exit commands can be used.
4. SA = sector addresses:
SA = 03XXX for PARAMETER BLOCK 1
SA = 05XXX for PARAMETER BLOCK 2
SA = 1FXXX for MAIN MEMORY ARRAY
5. When the boot block programming lockout feature is not enabled, the boot block and the main memory block will erase
together (from the same sector erase command). Once the boot region has been protected, only the main memory array
sector will erase when its sector erase command is issued.
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 OE
with Respect to Ground ...................................-0.6V to +13.5V
*NOTICE:
Stresses beyond those listed under “Absolute
Maximum Ratings” may cause permanent dam-
age to the device. This is a stress rating only and
functional operation of the device at these or any
other conditions beyond those indicated in the
operational sections of this specification is not
implied. Exposure to absolute maximum rating
conditions for extended periods may affect device
reliability.
4
AT49F2048
AT49F2048
DC and AC Operating Range
AT49F2048-70
Operating
Temperature (Case)
V
CC
Power Supply
Com.
Ind.
0°C - 70°C
-40°C - 85°C
5V
±
10%
AT49F2048-90
0°C - 70°C
-40°C - 85°C
5V
±
10%
AT49F2048-12
0°C - 70°C
-40°C - 85°C
5V
±
10%
Operating Modes
Mode
Read
Program/Erase
(2)
Standby/Write Inhibit
Program Inhibit
Program Inhibit
Output Disable
Reset
Product Identification
A1 - A16 = VIL, A9 = V
H
,
(3)
A0 = V
IL
A1 - A16 = V
IL
, A9 = V
H
,
(3)
A0 = V
IH
A0 = VIL, A1 - A16 = V
IL
A0 = V
IH
, A1 - A16 = V
IL
Manufacturer Code
(4)
Device Code
(4)
Manufacturer Code
(4)
Device Code
(4)
CE
V
IL
V
IL
V
IH
X
X
X
X
OE
V
IL
V
IH
X
(1)
X
V
IL
V
IH
X
WE
V
IH
V
IL
X
V
IH
X
X
X
RESET
V
IH
V
IH
V
IH
V
IH
V
IH
V
IH
V
IL
Ai
Ai
Ai
X
I/O
D
OUT
D
IN
High Z
High Z
X
High Z
Hardware
V
IL
V
IL
V
IH
V
IH
Software
(5)
V
IH
Notes:
1. X can be V
IL
or V
IH
.
2. Refer to AC Programming Waveforms.
3. V
H
= 12.0V
±
0.5V.
4. Manufacturer Code: 1FH, Device Code: 82H
5. See details under Software Product Identification Entry/Exit.
DC Characteristics
Symbol
I
LI
I
LO
I
SB1
I
SB2
I
CC(1)
V
IL
V
IH
V
OL
V
OH1
V
OH2
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
Output High Voltage CMOS
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
Min
Max
10
10
300
3
50
0.8
Units
µA
µA
µA
mA
mA
V
V
2.0
I
OL
= 2.1 mA
I
OH
= -400
µA
I
OH
= -100
µA;
V
CC
= 4.5V
2.4
4.2
.45
V
V
V
Note:
1. In the erase mode, I
CC
is 90 mA.
5
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