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AT49F040B Datasheet(PDF) 3 Page - ATMEL Corporation

Part No. AT49F040B
Description  4-megabit (512K x 8) 5-volt Only Flash Memory
Download  19 Pages
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Maker  ATMEL [ATMEL Corporation]
Homepage  http://www.atmel.com
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AT49F040B Datasheet(HTML) 3 Page - ATMEL Corporation

 
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3
3606A–FLASH–12/05
AT49F040B
3.
Block Diagram
4.
Device Operation
4.1
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 com-
mand sequences are entered into the device. The command sequences are shown in the
Command Definitions table. The command sequences are written 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.
4.2
Read
The AT49F040B 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 con-
trol gives designers flexibility in preventing bus contention.
4.3
Erase
Before a byte can be reprogrammed, it must be erased. The erased state of memory bits is a
logical “1”. The entire device can be erased by using the Chip Erase command or individual sec-
tors can be erased by using the Sector Erase command.
CONTROL
LOGIC
Y DECODER
PARAMETER
SECTOR 1
(8K BYTES)
BOOT SECTOR
(16K BYTES)
OE
WE
CE
ADDRESS
INPUTS
VCC
GND
DATA INPUTS/OUTPUTS
I/O7 - I/O0
8
X DECODER
PARAMETER
SECTOR 2
(8K BYTES)
MAIN MEMORY
SECTOR 1
(32K BYTES)
MAIN MEMORY
SECTOR 2
(64K BYTES)
MAIN MEMORY
SECTOR 3
(64K BYTES)
MAIN MEMORY
SECTOR 4
(64K BYTES)
MAIN MEMORY
SECTOR 8
(64K BYTES)
MAIN MEMORY
SECTOR 7
(64K BYTES)
MAIN MEMORY
SECTOR 6
(64K BYTES)
MAIN MEMORY
SECTOR 5
(64K BYTES)
PROGRAM
DATA LATCHES
Y-GATING
INPUT/OUTPUT
BUFFERS
1FFFF
10000
0FFFF
08000
3FFFF
30000
2FFFF
20000
07FFF
06000
05FFF
04000
03FFF
00000
7FFFF
70000
6FFFF
60000
5FFFF
50000
4FFFF
40000


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