AT45DB ATMEL Corporation, AT45DB Datasheet - Page 3

• Manufacturer Part Number: AT45DB
• Description: 1-Megabit 2.7-volt Only Serial DataFlash
• Manufacturer: ATMEL Corporation

Memory Architecture Diagram
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 1 and 2. A valid instruc-
tion starts with the falling edge of CS followed by the appro-
priate 8-bit opcode and the desired buffer or main memory
address location. While the CS pin is low, toggling the SCK
pin controls the 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.
Read
By specifying the appropriate opcode, data can be read
from the main memory or from the data buffer.
MAIN MEMORY PAGE READ: A main memory read allows
the user to read data directly from any one of the 512
pages in the main memory, bypassing the data buffer and
leaving the contents of the buffer unchanged. To start a
page read, the 8-bit opcode, 52H, is followed by 24
address bits and 32 don’t care bits. In the AT45DB011, the
first six address bits are reserved for larger density devices
(see Notes on page 9), the next nine address bits (PA8-
PA0) specify the page address, and the next nine address
bits (BA8-BA0) specify the starting byte address within the
page. The 32 don’t care bits which follow the 24 address
SECTOR 1 = 65,472 BYTES (62K + 1984)
SECTOR 2 = 67,584 BYTES (64K + 2K)
SECTOR ARCHITECTURE
SECTOR 0 = 2112 BYTES (2K + 64)
SECTOR 0
BLOCK ARCHITECTURE
Block = 2112 bytes
BLOCK 61
BLOCK 62
BLOCK 63
BLOCK 29
BLOCK 30
BLOCK 31
BLOCK 32
BLOCK 33
BLOCK 34
BLOCK 0
BLOCK 1
BLOCK 2
BLOCK 3
(2K + 64)
bits are sent to initialize the read operation. Following the
32 don’t care bits, additional pulses on SCK result in serial
data being output on the SO (serial output) pin. The CS pin
must remain low during the loading of the opcode, the
address bits, and the reading of data. When the end of a
page in main memory is reached during a main memory
page read, the device will continue reading at the beginning
of the same page. A low to high transition on the CS pin will
terminate the read operation and tri-state the SO pin.
BUFFER READ: Data can be read from the data buffer
using an opcode of 54H. To perform a buffer read, the eight
bits of the opcode must be followed by 15 don’t care bits,
nine address bits, and eight don't care bits. Since the buffer
size is 264-bytes, nine address bits (BFA8-BFA0) are
required to specify the first byte of data to be read from the
buffer. The CS pin must remain low during the loading of
the opcode, the address bits, the don’t care bits, and the
reading of data. When the end of the buffer is reached, the
device will continue reading back at the beginning of the
buffer. A low to high transition on the CS pin will terminate
the read operation and tri-state the SO pin.
MAIN MEMORY PAGE TO BUFFER TRANSFER: A page
of data can be transferred from the main memory to buffer.
An 8-bit opcode of 53H is followed by the six reserved bits,
nine address bits (PA8-PA0) which specify the page in
8 Pages
PAGE ARCHITECTURE
Page = 264 bytes
PAGE 509
PAGE 510
PAGE 511
PAGE 14
PAGE 15
PAGE 16
PAGE 17
PAGE 18
PAGE 0
PAGE 1
PAGE 6
PAGE 7
PAGE 8
PAGE 9
(256 + 8)
3