ATMEL AT45DB021D User Manual
Features
• Single 2.7V to 3.6V Supply
• RapidS Serial Interface: 66 MHz Maximum Clock Frequency
– SPI Compatible Modes 0 and 3
• User Configurable Page Size
– 256 Bytes per Page
– 264 Bytes per Page
– Page Size Can Be Factory Pre-configured for 256 Bytes
• Page Program Operation
– Intelligent Programming Operation
– 1,024 Pages (256/264 Bytes/Page) Main Memory
• Flexible Erase Options
– Page Erase (256 Bytes)
– Block Erase (2 Kbytes)
– Sector Erase (32 Kbytes)
– Chip Erase (2 Mbits)
• One SRAM Data Buffer (256/264 Bytes)
• Continuous Read Capability through Entire Array
– Ideal for Code Shadowing Applications
• Low-power Dissipation
– 7 mA Active Read Current Typical
– 25 µA Standby Current Typical
– 15 µA Deep Power-down Typical
• Hardware and Software Data Protection Features
– Individual Sector
• Sector Lockdown for Secure Code and Data Storage
– Individual Sector
• Security: 128-byte Security Register
– 64-byte User Programmable Space
– Unique 64-byte Device Identifier
• JEDEC Standard Manufacturer and Device ID Read
• 100,000 Program/Erase Cycles Per Page Minimum
• Data Retention – 20 Years
• Industrial Temperature Range
• Green (Pb/Halide-free/RoHS Compliant) Packaging Options
2-megabit
2.7-volt
Minimum
DataFlash
®
AT45DB021D
1. Description
The AT45DB021D is a 2.7V, serial-interface Flash memory ideally suited for a wide
variety of digital voice-, image-, program code- and data-storage applications. The
AT45DB021D supports RapidS serial interface for applications requiring very high
speed operations. RapidS serial interface is SPI compatible for frequencies up to 66
MHz. Its 2,162,688 bits of memory are organized as 1,024 pages of 256 bytes or 264
bytes each. In addition to the main memory, the AT45DB021D also contains one
SRAM buffer of 256/264 bytes. EEPROM emulation (bit or byte alterability) is easily
handled with a self-contained three step read-modify-write operation. Unlike conventional Flash memories that are accessed randomly with multiple address lines and a
parallel interface, the DataFlash
access its data. The simple sequential access dramatically reduces active pin count,
facilitates hardware layout, increases system reliability, minimizes switching noise,
and reduces package size.
®
uses a RapidS serial interface to sequentially
3638I–DFLASH–04/09
The device is optimized for use in many commercial and industrial applications where high-density, low-pin count, low-voltage and low-power are essential.
To allow for simple in-system reprogrammability, the AT45DB021D does not require high input
voltages for programming. The device operates from a single power supply, 2.7V to 3.6V, for
both the program and read operations. The AT45DB021D is enabled through the chip select pin
(CS
) and accessed via a three-wire interface consisting of the Serial Input (SI), Serial Output
(SO), and the Serial Clock (SCK).
All programming and erase cycles are self-timed.
2. Pin Configurations and Pinouts
Table 2-1. Pin Configurations
Asserted
Symbol Name and Function
Chip Select: Asserting the CS pin selects the device. When the CS pin is deasserted, the device will be deselected
and normally be placed in the standby mode (not Deep Power-Down mode), and the output pin (SO) will be in a
CS
SCK
SI
SO
WP
RESET
V
CC
GND Ground: The ground reference for the power supply. GND should be connected to the system ground. – Ground
high-impedance state. When the device is deselected, data will not be accepted on the input pin (SI).
A high-to-low transition on the CS
end an operation. When ending an internally self-timed operation such as a program or erase cycle, the device
will not enter the standby mode until the completion of the operation.
Serial Clock: This pin is used to provide a clock to the device and is used to control the flow of data to and from
the device. Command, address, and input data present on the SI pin is always latched on the rising edge of SCK,
while output data on the SO pin is always clocked out on the falling edge of SCK.
Serial Input: The SI pin is used to shift data into the device. The SI pin is used for all data input including
command and address sequences. Data on the SI pin is always latched on the rising edge of SCK.
Serial Output: The SO pin is used to shift data out from the device. Data on the SO pin is always clocked out on
the falling edge of SCK.
Write Protect: When the WP pin is asserted, all sectors specified for protection by the Sector Protection Register
will be protected against program and erase operations regardless of whether the Enable Sector Protection
command has been issued or not. The WP
After the WP
If a program or erase command is issued to the device while the WP
the command and perform no operation. The device will return to the idle state once the CS
deasserted. The Enable Sector Protection command and Sector Lockdown command, however, will be
recognized by the device when the WP
The WP
However, it is recommended that the WP
Reset: A low state on the reset pin (RESET
machine to an idle state. The device will remain in the reset condition as long as a low level is present on the RESET
pin. Normal operation can resume once the RESET
The device incorporates an internal power-on reset circuit, so there are no restrictions on the RESET
power-on sequences. If this pin and feature are not utilized it is recommended that the RESET
externally.
Device Power Supply: The VCC pin is used to supply the source voltage to the device.
Operations at invalid V
pin goes low, the content of the Sector Protection Register cannot be modified.
pin is internally pulled-high and may be left floating if hardware controlled protection will not be used.
voltages may produce spurious results and should not be attempted.
CC
pin is required to start an operation, and a low-to-high transition is required to
pin functions independently of the software controlled protection method.
pin is asserted, the device will simply ignore
pin has been
pin is asserted.
pin also be externally connected to VCC whenever possible.
) will terminate the operation in progress and reset the internal state
pin is brought back to a high level.
pin during
pin be driven high
State Type
Low Input
– Input
– Input
– Output
Low Input
Low Input
– Power
2
AT45DB021D
3638I–DFLASH–04/09
AT45DB021D
1
2
3
4
8
7
6
5
SI
SCK
RESET
CS
SO
GND
VCC
WP
SI
SCK
RESET
CS
SO
GND
VCC
WP
8
7
6
5
1
2
3
4
FLASH MEMORY ARRAY
PAGE (256/264 BYTES)
BUFFER (256/264 BYTES)
I/O INTERFACE
SCK
CS
RESET
VCC
GND
WP
SOSI
Figure 2-1. SOIC Top View Figure 2-2. UDFN Top View
(1)
Note: 1. The metal pad on the bottom of the UDFN package is floating. This pad can be a “No Connect” or connected to GND.
3. Block Diagram
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3
4. Memory Array
To provide optimal flexibility, the memory array of the AT45DB021D is divided into three levels of
granularity comprising of sectors, blocks, and pages. The “Memory Architecture Diagram” illustrates the breakdown of each level and details the number of pages per sector and block. All
program operations to the DataFlash occur on a page-by-page basis. The erase operations can
be performed at the chip, sector, block or page level.
Figure 4-1. Memory Architecture Diagram
SECTOR ARCHITECTURE BLOCK ARCHITECTURE PAGE ARCHITECTURE
SECTOR 0a = 8 Pages
2,048/2,112 bytes
SECTOR 0a
BLOCK 0
BLOCK 1
BLOCK 2
8 Pages
PAGE 0
PAGE 1
SECTOR 0b = 120 Pages
31,744/32,726 bytes
SECTOR 1 = 128 Pages
32,768/33,792 bytes
SECTOR 6 = 128 Pages
32,768/33,792 bytes
SECTOR 7 = 128 Pages
32,768/33,792 bytes
5. Device Operation
The device operation is controlled by instructions from the host processor. The list of instructions
and their associated opcodes are contained in Tables 15-1 through 15-7. A valid instruction
starts with the falling edge of CS
or main memory address location. While the CS
loading of the opcode and the desired buffer or main memory address location through the SI
(serial input) pin. All instructions, addresses, and data are transferred with the most significant
bit (MSB) first.
SECTOR 0b
SECTOR 1
Block = 1,024/1,056 bytes
BLOCK 0
BLOCK 14
BLOCK 15
BLOCK 16
BLOCK 17
BLOCK 1
BLOCK 30
BLOCK 31
BLOCK 32
BLOCK 33
BLOCK 126
BLOCK 127
PAGE 6
PAGE 7
PAGE 8
PAGE 9
PAGE 14
PAGE 15
PAGE 16
PAGE 17
PAGE 18
PAGE 1,022
PAGE 1,023
Page = 256/264 bytes
followed by the appropriate 8-bit opcode and the desired buffer
pin is low, toggling the SCK pin controls the
Buffer addressing for the DataFlash standard page size (264 bytes) is referenced in the
datasheet using the terminology BFA8 - BFA0 to denote the 9 address bits required to designate
a byte address within a buffer. Main memory addressing is referenced using the terminology
PA9 - PA0 and BA8 - BA0, where PA9 - PA0 denotes the 10 address bits required to designate
a page address and BA8 - BA0 denotes the 9 address bits required to designate a byte address
within the page.
For the “Power of 2” binary page size (256 bytes), the Buffer addressing is referenced in the
datasheet using the conventional terminology BFA7 - BFA0 to denote the 8 address bits
required to designate a byte address within a buffer. Main memory addressing is referenced
using the terminology A17 - A0, where A17 - A8 denotes the 10 address bits required to designate a page address and A7 - A0 denotes the 8 address bits required to designate a byte
address within a page.
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AT45DB021D
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6. Read Commands
By specifying the appropriate opcode, data can be read from the main memory or from the
SRAM data buffer. The DataFlash supports RapidS protocols for Mode 0 and Mode 3. Please
refer to the “Detailed Bit-level Read Timing” diagrams in this datasheet for details on the clock
cycle sequences for each mode.
6.1 Continuous Array Read (Legacy Command – E8H): Up to 66 MHz
By supplying an initial starting address for the main memory array, the Continuous Array Read
command can be utilized to sequentially read a continuous stream of data from the device by
simply providing a clock signal; no additional addressing information or control signals need to
be provided. The DataFlash incorporates an internal address counter that will automatically
increment on every clock cycle, allowing one continuous read operation without the need of
additional address sequences. To perform a continuous read from the DataFlash standard page
size (264 bytes), an opcode of E8H must be clocked into the device followed by three address
bytes (which comprise the 24-bit page and byte address sequence) and 4 don’t care bytes. The
first 10 bits (PA9 - PA0) of the 19-bit address sequence specify which page of the main memory
array to read, and the last 9 bits (BA8 - BA0) of the 19-bit address sequence specify the starting
byte address within the page. To perform a continuous read from the binary page size (256
bytes), the opcode (E8H) must be clocked into the device followed by three address bytes and 4
don’t care bytes. The first 10 bits (A17 - A8) of the 18-bits sequence specify which page of the
main memory array to read, and the last 8 bits (A7 - A0) of the 18-bits address sequence specify
the starting byte address within the page. The don’t care bytes that follow the address bytes are
needed to initialize the read operation. Following the don’t care bytes, additional clock pulses on
the SCK pin will result in data being output on the SO (serial output) pin.
AT45DB021D
The CS
bytes, and the reading of data. When the end of a page in main memory is reached during a
Continuous Array Read, the device will continue reading at the beginning of the next page with
no delays incurred during the page boundary crossover (the crossover from the end of one page
to the beginning of the next page). When the last bit in the main memory array has been read,
the device will continue reading back at the beginning of the first page of memory. As with crossing over page boundaries, no delays will be incurred when wrapping around from the end of the
array to the beginning of the array.
A low-to-high transition on the CS
pin (SO). The maximum SCK frequency allowable for the Continuous Array Read is defined by
the f
contents of the buffer unchanged.
pin must remain low during the loading of the opcode, the address bytes, the don’t care
pin will terminate the read operation and tri-state the output
specification. The Continuous Array Read bypasses the data buffer and leaves the
CAR1
6.2 Continuous Array Read (High Frequency Mode – 0BH): Up to 66 MHz
This command can be used with the serial interface to read the main memory array sequentially
in high speed mode for any clock frequency up to the maximum specified by f
continuous read array with the page size set to 264 bytes, the CS
opcode 0BH must be clocked into the device followed by three address bytes and a dummy
byte. The first 10 bits (PA9 - PA0) of the 19-bit address sequence specify which page of the
main memory array to read, and the last 9 bits (BA8 - BA0) of the 19-bit address sequence specify the starting byte address within the page. To perform a continuous read with the page size
set to 256 bytes, the opcode, 0BH, must be clocked into the device followed by three address
bytes (A17 - A0) and a dummy byte. Following the dummy byte, additional clock pulses on the
SCK pin will result in data being output on the SO (serial output) pin.
must first be asserted then an
. To perform a
CAR1
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5
The CS pin must remain low during the loading of the opcode, the address bytes, and the reading of data. When the end of a page in the main memory is reached during a Continuous Array
Read, the device will continue reading at the beginning of the next page with no delays incurred
during the page boundary crossover (the crossover from the end of one page to the beginning of
the next page). When the last bit in the main memory array has been read, the device will continue reading back at the beginning of the first page of memory. As with crossing over page
boundaries, no delays will be incurred when wrapping around from the end of the array to the
beginning of the array. A low-to-high transition on the CS pin will terminate the read operation
and tri-state the output pin (SO). The maximum SCK frequency allowable for the Continuous
Array Read is defined by the f
buffer and leaves the contents of the buffer unchanged.
specification. The Continuous Array Read bypasses the data
CAR1
6.3 Continuous Array Read (Low Frequency Mode: 03H): Up to 33 MHz
This command can be used with the serial interface to read the main memory array sequentially
without a dummy byte up to maximum frequencies specified by f
read array with the page size set to 264 bytes, the CS
03H, must be clocked into the device followed by three address bytes (which comprise the 24-bit
page and byte address sequence). The first 10 bits (PA9 - PA0) of the 19-bit address sequence
specify which page of the main memory array to read, and the last 9 bits (BA8 - BA0) of the
19-bit address sequence specify the starting byte address within the page. To perform a continuous read with the page size set to 256 bytes, the opcode, 03H, must be clocked into the device
followed by three address bytes (A17 - A0). Following the address bytes, additional clock pulses
on the SCK pin will result in data being output on the SO (serial output) pin.
must first be asserted then an opcode,
CAR2
. To perform a continuous
The CS pin must remain low during the loading of the opcode, the address bytes, and the reading of data. When the end of a page in the main memory is reached during a Continuous Array
Read, the device will continue reading at the beginning of the next page with no delays incurred
during the page boundary crossover (the crossover from the end of one page to the beginning of
the next page). When the last bit in the main memory array has been read, the device will continue reading back at the beginning of the first page of memory. As with crossing over page
boundaries, no delays will be incurred when wrapping around from the end of the array to the
beginning of the array. A low-to-high transition on the CS pin will terminate the read operation
and tri-state the output pin (SO). The Continuous Array Read bypasses the data buffer and
leaves the contents of the buffer unchanged.
6.4 Main Memory Page Read
A main memory page read allows the user to read data directly from any one of the 2,048 pages
in the main memory, bypassing the data buffer and leaving the contents of the buffer
unchanged. To start a page read from the DataFlash standard page size (264 bytes), an opcode
of D2H must be clocked into the device followed by three address bytes (which comprise the
24-bit page and byte address sequence) and 4 don’t care bytes. The first 10 bits (PA9 - PA0) of
the 19-bit address sequence specify the page in main memory to be read, and the last 9 bits
(BA8 - BA0) of the 19-bit address sequence specify the starting byte address within that page.
To start a page read from the binary page size (256 bytes), the opcode D2H must be
clocked into the device followed by three address bytes and 4 don’t care bytes. The first 10 bits
(A17 - A8) of the 18-bit sequence specify which page of the main memory array to read, and the
last 8 bits (A7 - A0) of the 18-bit address sequence specify the starting byte address within the
page. The don’t care bytes that follow the address bytes are sent to initialize the read operation.
Following the don’t care bytes, additional pulses on SCK result in data being output on the SO
(serial output) pin. The CS
bytes, the don’t care bytes, and the reading of data. When the end of a page in main memory is
pin must remain low during the loading of the opcode, the address
6
AT45DB021D
3638I–DFLASH–04/09
6.5 Buffer Read
AT45DB021D
reached, the device will continue reading back at the beginning of the same page. A low-to-high
transition on the CS
maximum SCK frequency allowable for the Main Memory Page Read is defined by the f
specification. The Main Memory Page Read bypasses the data buffer and leaves the contents of
the buffer unchanged.
The SRAM data buffer can be accessed independently from the main memory array, and utilizing the Buffer Read Command allows data to be sequentially read directly from the buffer. Two
opcodes, D4H or D1H, can be used for the Buffer Read Command. The use of each opcode
depends on the maximum SCK frequency that will be used to read data from the buffer. The
D4H opcode can be used at any SCK frequency up to the maximum specified by f
opcode can be used for lower frequency read operations up to the maximum specified by f
To perform a buffer read from the DataFlash standard buffer (264 bytes), the opcode must be
clocked into the device followed by three address bytes comprised of 15 don’t care bits and
9 buffer address bits (BFA8 - BFA0). To perform a buffer read from the binary buffer (256 bytes),
the opcode must be clocked into the device followed by three address bytes comprised of
16 don’t care bits and 8 buffer address bits (BFA7 - BFA0). Following the address bytes, one
don’t care byte must be clocked in to initialize the read operation. The CS
during the loading of the opcode, the address bytes, the don’t care bytes, and the reading of
data. When the end of a buffer is reached, the device will continue reading back at the beginning
of the buffer. A low-to-high transition on the CS
the output pin (SO).
pin will terminate the read operation and tri-state the output pin (SO). The
SCK
. The D1H
CAR1
CAR2
pin must remain low
pin will terminate the read operation and tri-state
.
7. Program and Erase Commands
7.1 Buffer Write
Data can be clocked in from the input pin (SI) into the buffer. To load data into the DataFlash
standard buffer (264 bytes), a 1-byte opcode, 84H, must be clocked into the device followed by
three address bytes comprised of 15 don’t care bits and 9 buffer address bits (BFA8 - BFA0).
The 9 buffer address bits specify the first byte in the buffer to be written. To load data into the
binary buffers (256 bytes each), a 1-byte opcode, 84H, must be clocked into the device followed
by three address bytes comprised of 16 don’t care bits and 8 buffer address bits (BFA7 - BFA0).
The 8 buffer address bits specify the first byte in the buffer to be written. After the last address
byte has been clocked into the device, data can then be clocked in on subsequent clock cycles.
If the end of the data buffer is reached, the device will wrap around back to the beginning of the
buffer. Data will continue to be loaded into the buffer until a low-to-high transition is detected on
the CS
7.2 Buffer to Main Memory Page Program with Built-in Erase
Data written into the buffer can be programmed into the main memory. A 1-byte opcode, 83H,
must be clocked into the device. For the DataFlash standard page size (264 bytes), the opcode
must be followed by three address bytes consist of 5 don’t care bits, 10 page address bits
(PA9 - PA0) that specify the page in the main memory to be written and 9 don’t care bits. To perform a buffer to main memory page program with built-in erase for the binary page size (256
bytes), the opcode 83H must be clocked into the device followed by three address bytes consisting of 6 don’t care bits, 10 page address bits (A17 - A8) that specify the page in the main
memory to be written and 8 don’t care bits. When a low-to-high transition occurs on the CS
pin.
pin,
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7
the part will first erase the selected page in main memory (the erased state is a logic 1) and then
program the data stored in the buffer into the specified page in main memory. Both the erase
and the programming of the page are internally self-timed and should take place in a maximum
time of t
. During this time, the status register will indicate that the part is busy.
EP
7.3 Buffer to Main Memory Page Program without Built-in Erase
A previously-erased page within main memory can be programmed with the contents of the buffer. A 1-byte opcode, 88H, must be clocked into the device. For the DataFlash standard page
size (264 bytes), the opcode must be followed by three address bytes consist of 5 don’t care
bits, 10 page address bits (PA9 - PA0) that specify the page in the main memory to be written
and 9 don’t care bits. To perform a buffer to main memory page program without built-in erase
for the binary page size (256 bytes), the opcode 88H must be clocked into the device followed
by three address bytes consisting of 6 don’t care bits, 10 page address bits (A17 - A8) that specify the page in the main memory to be written and 8 don’t care bits. When a low-to-high transition
occurs on the CS
pin, the part will program the data stored in the buffer into the specified page in
the main memory. It is necessary that the page in main memory that is being programmed has
been previously erased using one of the erase commands (Page Erase or Block Erase). The
programming of the page is internally self-timed and should take place in a maximum time of t
During this time, the status register will indicate that the part is busy.
7.4 Page Erase
The Page Erase command can be used to individually erase any page in the main memory array
allowing the Buffer to Main Memory Page Program to be utilized at a later time. To perform a
page erase in the DataFlash standard page size (264 bytes), an opcode of 81H must be loaded
into the device, followed by three address bytes comprised of 5 don’t care bits, 10 page address
bits (PA9 - PA0) that specify the page in the main memory to be erased and 9 don’t care bits. To
perform a page erase in the binary page size (256 bytes), the opcode 81H must be loaded into
the device, followed by three address bytes consist of 6 don’t care bits, 10 page address bits
(A17 - A8) that specify the page in the main memory to be erased and 8 don’t care bits. When a
low-to-high transition occurs on the CS
state is a logical 1). The erase operation is internally self-timed and should take place in a maximum time of t
. During this time, the status register will indicate that the part is busy.
PE
pin, the part will erase the selected page (the erased
.
P
7.5 Block Erase
8
AT45DB021D
A block of eight pages can be erased at one time. This command is useful when large amounts
of data has to be written into the device. This will avoid using multiple Page Erase Commands.
To perform a block erase for the DataFlash standard page size (264 bytes), an opcode of 50H
must be loaded into the device, followed by three address bytes comprised of 5 don’t care bits,
7 page address bits (PA9 -PA3) and 12 don’t care bits. The 7 page address bits are used to
specify which block of eight pages is to be erased. To perform a block erase for the binary page
size (256 bytes), the opcode 50H must be loaded into the device, followed by three address
bytes consisting of 6 don’t care bits, 7 page address bits (A17 - A11) and 11 don’t care bits. The
9 page address bits are used to specify which block of eight pages is to be erased. When a lowto-high transition occurs on the CS
erase operation is internally self-timed and should take place in a maximum time of t
pin, the part will erase the selected block of eight pages. The
. During
BE
this time, the status register will indicate that the part is busy.
3638I–DFLASH–04/09
AT45DB021D
Table 7-1. Block Erase Addressing
PA9 /
A17
0000000XXX 0
0000001XXX 1
0000010XXX 2
0000011XXX 3
PA8 /
A16
PA7 /
A15
PA6 /
A14
PA5 /
A13
PA4/
A12
PA3/
A11
PA2/
A10
PA1 /
A9
PA0 /
A8 Block
•
•
•
1111100XXX 124
1111101XXX 125
1111110XXX 126
1111111XXX 127
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
7.6 Sector Erase
The Sector Erase command can be used to individually erase any sector in the main memory.
There are 4 sectors and only one sector can be erased at one time. To perform sector 0a or sector 0b erase for the DataFlash standard page size (264 bytes), an opcode of 7CH must be
loaded into the device, followed by three address bytes comprised of 5 don’t care bits, 7 page
address bits (PA9 - PA3) and 12 don’t care bits. To perform a sector 1-7 erase, the opcode 7CH
must be loaded into the device, followed by three address bytes comprised of 5 don’t care bits, 3
page address bits (PA9 - PA7) and 16 don’t care bits. To perform sector 0a or sector 0b erase
for the binary page size (256 bytes), an opcode of 7CH must be loaded into the device, followed
by three address bytes comprised of 6 don’t care bits and 7 page address bits (A17 - A11) and
11 don’t care bits. To perform a sector 1-7 erase, the opcode 7CH must be loaded into the
device, followed by three address bytes comprised of 6 don’t care bit and 3 page address bits
(A17 - A15) and 16 don’t care bits. The page address bits are used to specify any valid address
location within the sector which is to be erased. When a low-to-high transition occurs on the CS
pin, the part will erase the selected sector. The erase operation is internally self-timed and
should take place in a maximum time of t
the part is busy.
. During this time, the status register will indicate that
SE
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Table 7-2. Sector Erase Addressing
Opcode
Byte 1
Opcode
Byte 2
Opcode
Byte 3
Opcode
Byte 4
CS
Each transition
represents 8 bits
SI
PA9 /
A17
0000000XXX 0a
0000001XXX 0b
•
•
•
01 1 XXXXXXX 5
10 0 XXXXXXX 6
11 1 XXXXXXX 7
PA8 /
A16
•
•
•
PA7 /
A15
•
•
•
PA6 /
A14
•
•
•
PA5 /
A13
•
•
•
PA4/
A12
•
•
•
PA3/
A11
•
•
•
PA2/
A10
•
•
•
PA1 /
A9
•
•
•
PA0 /
A8 Sector
•
•
•
7.7 Chip Erase
The entire main memory can be erased at one time by using the Chip Erase command.
To execute the Chip Erase command, a 4-byte command sequence C7H, 94H, 80H and 9AH
must be clocked into the device. Since the entire memory array is to be erased, no address
bytes need to be clocked into the device, and any data clocked in after the opcode will be
ignored. After the last bit of the opcode sequence has been clocked in, the CS
serted to start the erase process. The erase operation is internally self-timed and should take
place in a time of t
. During this time, the Status Register will indicate that the device is busy.
CE
The Chip Erase command will not affect sectors that are protected or locked down; the contents
of those sectors will remain unchanged. Only those sectors that are not protected or locked
down will be erased.
pin can be deas-
•
•
•
The WP
pin can be asserted while the device is erasing, but protection will not be activated until
the internal erase cycle completes.
Command Byte 1 Byte 2 Byte 3 Byte 4
Chip Erase C7H 94H 80H 9AH
Figure 7-1. Chip Erase
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AT45DB021D
3638I–DFLASH–04/09
7.8 Main Memory Page Program Through Buffer
This operation is a combination of the Buffer Write and Buffer to Main Memory Page Program
with Built-in Erase operations. Data is first clocked into the buffer from the input pin (SI) and then
programmed into a specified page in the main memory. To perform a main memory page program through buffer for the DataFlash standard page size (264 bytes), a 1-byte opcode, 82H,
must first be clocked into the device, followed by three address bytes. The address bytes are
comprised of 5 don’t care bits, 10 page address bits, (PA9 - PA0) that select the page in the
main memory where data is to be written, and 9 buffer address bits (BFA8 - BFA0) that select
the first byte in the buffer to be written. To perform a main memory page program through buffer
for the binary page size (256 bytes), the opcode 82H must be clocked into the device followed
by three address bytes consisting of 6 don’t care bits, 10 page address bits (A17 - A8) that specify the page in the main memory to be written, and 8 buffer address bits (BFA7 - BFA0) that
selects the first byte in the buffer to be written. After all address bytes are clocked in, the part will
take data from the input pins and store it in the specified data buffer. If the end of the buffer is
reached, the device will wrap around back to the beginning of the buffer. When there is a low-tohigh transition on the CS
and then program the data stored in the buffer into that memory page. Both the erase and the
programming of the page are internally self-timed and should take place in a maximum time of
t
. During this time, the status register will indicate that the part is busy.
EP
pin, the part will first erase the selected page in main memory to all 1s
AT45DB021D
8. Sector Protection
Two protection methods, hardware and software controlled, are provided for protection against
inadvertent or erroneous program and erase cycles. The software controlled method relies on
the use of software commands to enable and disable sector protection while the hardware controlled method employs the use of the Write Protect (WP
that are to be protected or unprotected against program and erase operations is specified in the
nonvolatile Sector Protection Register. The status of whether or not sector protection has been
enabled or disabled by either the software or the hardware controlled methods can be determined by checking the Status Register.
) pin. The selection of which sectors
3638I–DFLASH–04/09
11
8.1 Software Sector Protection
8.1.1 Enable Sector Protection Command
Sectors specified for protection in the Sector Protection Register can be protected from program
and erase operations by issuing the Enable Sector Protection command. To enable the sector
protection using the software controlled method, the CS
with any other command. Once the CS
sequence must be clocked in via the input pin (SI). After the last bit of the command sequence
has been clocked in, the CS
enabled.
Command Byte 1 Byte 2 Byte 3 Byte 4
Enable Sector Protection 3DH 2AH 7FH A9H
Figure 8-1. Enable Sector Protection
CS
pin must first be asserted as it would be
pin has been asserted, the appropriate 4-byte command
pin must be deasserted after which the sector protection will be
SI
8.1.2 Disable Sector Protection Command
To disable the sector protection using the software controlled method, the CS
asserted as it would be with any other command. Once the CS
appropriate 4-byte sequence for the Disable Sector Protection command must be clocked in via
the input pin (SI). After the last bit of the command sequence has been clocked in, the CS
must be deasserted after which the sector protection will be disabled. The WP
deasserted state; otherwise, the Disable Sector Protection command will be ignored.
Command Byte 1 Byte 2 Byte 3 Byte 4
Disable Sector Protection 3DH 2AH 7FH 9AH
Figure 8-2. Disable Sector Protection
CS
SI
Opcode
Byte 1
Each transition
represents 8 bits
Opcode
Byte 1
Each transition
represents 8 bits
Opcode
Byte 2
Opcode
Byte 2
Opcode
Byte 3
Opcode
Byte 3
Opcode
Byte 4
pin must first be
pin has been asserted, the
pin must be in the
Opcode
Byte 4
pin
8.1.3 Various Aspects About Software Controlled Protection
Software controlled protection is useful in applications in which the WP
controlled by a host processor. In such instances, the WP
internally pulled high) and sector protection can be controlled using the Enable Sector Protection
and Disable Sector Protection commands.
If the device is power cycled, then the software controlled protection will be disabled. Once the
device is powered up, the Enable Sector Protection command should be reissued if sector pro-
12
tection is desired and if the WP
AT45DB021D
pin is not used.
pin is not or cannot be
pin may be left floating (the WP pin is
3638I–DFLASH–04/09
9. Hardware Controlled Protection
Sectors specified for protection in the Sector Protection Register and the Sector Protection Register itself can be protected from program and erase operations by asserting the WP
keeping the pin in its asserted state. The Sector Protection Register and any sector specified for
protection cannot be erased or reprogrammed as long as the WP
modify the Sector Protection Register, the WP
nently connected to GND, then the content of the Sector Protection Register cannot be changed.
If the WP
Protection Register can be modified.
pin is deasserted, or permanently connected to VCC, then the content of the Sector
AT45DB021D
pin and
pin is asserted. In order to
pin must be deasserted. If the WP pin is perma-
The WP
pin will override the software controlled protection method but only for protecting the
sectors. For example, if the sectors were not previously protected by the Enable Sector Protection command, then simply asserting the WP
maximum specified t
time. When the WP pin is deasserted; however, the sector protection
WPE
would no longer be enabled (after the maximum specified t
tor Protection command was not issued while the WP
Protection command was issued before or while the WP
ing the WP
pin would not disable the sector protection. In this case, the Disable Sector
Protection command would need to be issued while the WP
pin would enable the sector protection within the
time) as long as the Enable Sec-
WPD
pin was asserted. If the Enable Sector
pin was asserted, then simply deassert-
pin is deasserted to disable the sector protection. The Disable Sector Protection command is also ignored whenever the WP
asserted.
A noise filter is incorporated to help protect against spurious noise that may inadvertently assert
or deassert the WP
pin.
The table below details the sector protection status for various scenarios of the WP
Enable Sector Protection command, and the Disable Sector Protection command.
Figure 9-1. WP
Pin and Protection Status
12
3
WP
Table 9-1. WP Pin and Protection Status
Time
Period WP Pin
1High
2 Low X X Enabled Read Only
3High
Enable Sector Protection
Command
Command Not Issued Previously
–
Issue Command
Command Issued During Period 1
or 2
–
Issue Command
Disable Sector
Protection Command
X
Issue Command
–
Not Issued Yet
Issue Command
–
Sector Protection
Status
Disabled
Disabled
Enabled
Enabled
Disabled
Enabled
pin is
pin, the
Sector
Protection
Register
Read/Write
Read/Write
Read/Write
Read/Write
Read/Write
Read/Write
3638I–DFLASH–04/09
13
9.1 Sector Protection Register
The nonvolatile Sector Protection Register specifies which sectors are to be protected or unprotected with either the software or hardware controlled protection methods. The Sector Protection
Register contains 8 bytes of data, of which byte locations 0 through 7 contain values that specify
whether sectors 0 through 7 will be protected or unprotected. The Sector Protection Register is
user modifiable and must first be erased before it can be reprogrammed. Table 9-3 illustrates the
format of the Sector Protection Register.
Table 9-2. Sector Protection Register
Sector Number 0 (0a, 0b) 1 to 7
Protected
Unprotected 00H
Table 9-3. Sector 0 (0a, 0b)
Sectors 0a, 0b Unprotected 00 00 xx xx 0xH
Protect Sector 0a 11 00 xx xx CxH
Protect Sector 0b (Page 8-127) 00 11 xx xx 3xH
See Table 9-3
0a 0b
(Page 0-7) (Page 8-127)
Bit 7, 6 Bit 5, 4 Bit 1, 0
Bit 3, 2
FFH
Data
Val ue
Protect Sectors 0a (Page 0-7), 0b
(Page 8-127)
Note: 1. The default value for bytes 0 through 7 when shipped from Atmel® is 00H.
(1)
x = don’t care.
11 11 xx xx FxH
14
AT45DB021D
3638I–DFLASH–04/09
9.1.1 Erase Sector Protection Register Command
In order to modify and change the values of the Sector Protection Register, it must first be
erased using the Erase Sector Protection Register command.
AT45DB021D
To erase the Sector Protection Register, the CS
any other command. Once the CS
pin has been asserted, the appropriate 4-byte opcode
pin must first be asserted as it would be with
sequence must be clocked into the device via the SI pin. The 4-byte opcode sequence must
start with 3DH and be followed by 2AH, 7FH, and CFH. After the last bit of the opcode sequence
has been clocked in, the CS
cycle. The erasing of the Sector Protection Register should take place in a time of t
pin must be deasserted to initiate the internally self-timed erase
, during
PE
which time the Status Register will indicate that the device is busy. If the device is powereddown before the completion of the erase cycle, then the contents of the Sector Protection Register cannot be guaranteed.
The Sector Protection Register can be erased with the sector protection enabled or disabled.
Since the erased state (FFH) of each byte in the Sector Protection Register is used to indicate
that a sector is specified for protection, leaving the sector protection enabled during the erasing
of the register allows the protection scheme to be more effective in the prevention of accidental
programming or erasing of the device. If for some reason an erroneous program or erase command is sent to the device immediately after erasing the Sector Protection Register and before
the register can be reprogrammed, then the erroneous program or erase command will not be
processed because all sectors would be protected.
Command Byte 1 Byte 2 Byte 3 Byte 4
Erase Sector Protection Register 3DH 2AH 7FH CFH
Figure 9-2. Erase Sector Protection Register
CS
SI
Opcode
Byte 1
Each transition
represents 8 bits
Opcode
Byte 2
Opcode
Byte 3
Opcode
Byte 4
3638I–DFLASH–04/09
15
9.1.2 Program Sector Protection Register Command
Once the Sector Protection Register has been erased, it can be reprogrammed using the
Program Sector Protection Register command.
To program the Sector Protection Register, the CS
pin must first be asserted and the appropriate 4-byte opcode sequence must be clocked into the device via the SI pin. The 4-byte opcode
sequence must start with 3DH and be followed by 2AH, 7FH, and FCH. After the last bit of the
opcode sequence has been clocked into the device, the data for the contents of the Sector Protection Register must be clocked in. As described in Section 9.1, the Sector Protection Register
contains 4 bytes of data, so 4 bytes must be clocked into the device. The first byte of data corresponds to sector 0, the second byte corresponds to sector 1, the third byte corresponds to sector
2, and the last byte of data corresponding to sector 3.
After the last data byte has been clocked in, the CS
pin must be deasserted to initiate the internally self-timed program cycle. The programming of the Sector Protection Register should take
place in a time of t
, during which time the Status Register will indicate that the device is busy. If
P
the device is powered-down during the program cycle, then the contents of the Sector Protection
Register cannot be guaranteed.
If the proper number of data bytes is not clocked in before the CS
pin is deasserted, then the
protection status of the sectors corresponding to the bytes not clocked in can not be guaranteed.
For example, if only the first two bytes are clocked in instead of the complete 4 bytes, then the
protection status of the last 2 sectors cannot be guaranteed. Furthermore, if more than 4 bytes
of data is clocked into the device, then the data will wrap back around to the beginning of the
register. For instance, if 5 bytes of data are clocked in, then the 5th byte will be stored at byte
location 0 of the Sector Protection Register.
If a value other than 00H or FFH is clocked into a byte location of the Sector Protection Register,
then the protection status of the sector corresponding to that byte location cannot be guaranteed. For example, if a value of 17H is clocked into byte location 2 of the Sector Protection
Register, then the protection status of sector 2 cannot be guaranteed.
The Sector Protection Register can be reprogrammed while the sector protection enabled or disabled. Being able to reprogram the Sector Protection Register with the sector protection enabled
allows the user to temporarily disable the sector protection to an individual sector rather than
disabling sector protection completely.
The Program Sector Protection Register command utilizes the internal SRAM buffer for
processing. Therefore, the contents of the buffer will be altered from its previous state when this
command is issued.
Command Byte 1 Byte 2 Byte 3 Byte 4
Program Sector Protection Register 3DH 2AH 7FH FCH
Figure 9-3. Program Sector Protection Register
CS
16
SI
Each transition
represents 8 bits
Opcode
Byte 1
AT45DB021D
Opcode
Byte 2
Opcode
Byte 3
Opcode
Byte 4
Data Byte
n
Data Byte
n + 1
Data Byte
n + 3
3638I–DFLASH–04/09
9.1.3 Read Sector Protection Register Command
Opcode X X X
Data BytenData Byte
n + 1
CS
Data Byte
n + 3
SI
SO
Each transition
represents 8 bits
To read the Sector Protection Register, the CS
been asserted, an opcode of 32H and 3 dummy bytes must be clocked in via the SI pin. After the
last bit of the opcode and dummy bytes have been clocked in, any additional clock pulses on the
SCK pins will result in data for the content of the Sector Protection Register being output on the
SO pin. The first byte corresponds to sector 0 (0a, 0b), the second byte corresponds to sector 1,
the third byte corresponds to sector 2, and the last byte (byte 4) corresponds to sector 3. Once
the last byte of the Sector Protection Register has been clocked out, any additional clock pulses
will result in undefined data being output on the SO pin. The CS
nate the Read Sector Protection Register operation and put the output into a high-impedance
state.
Command Byte 1 Byte 2 Byte 3 Byte 4
Read Sector Protection Register 32H xxH xxH xxH
Note: xx = Dummy Byte
Figure 9-4. Read Sector Protection Register
AT45DB021D
pin must first be asserted. Once the CS pin has
must be deasserted to termi-
9.1.4 Various Aspects About the Sector Protection Register
The Sector Protection Register is subject to a limit of 10,000 erase/program cycles. Users are
encouraged to carefully evaluate the number of times the Sector Protection Register will be
modified during the course of the applications’ life cycle. If the application requires that the Sector Protection Register be modified more than the specified limit of 10,000 cycles because the
application needs to temporarily unprotect individual sectors (sector protection remains enabled
while the Sector Protection Register is reprogrammed), then the application will need to limit this
practice. Instead, a combination of temporarily unprotecting individual sectors along with disabling sector protection completely will need to be implemented by the application to ensure that
the limit of 10,000 cycles is not exceeded.
3638I–DFLASH–04/09
17
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