When the device is deselected, the CMOS standby current
is less than 100
µA.
For the AT49F002NT pin 1 for the DIP
and PLCC packages and pin 9 for the TSOP package are
no connect pins.
To allow for simple in-system reprogrammability, the
AT49F002(N)T does not require high input voltages for pro-
gramming. Five-volt-only commands determine the read
and programming operation of the device. Reading data
out of the device is similar to reading from an EPROM; it
has standard CE, OE, and WE inputs to avoid bus conten-
tion. Reprogramming the AT49F002(N)T is performed by
erasing a block of data and then programming on a byte by
byte basis. The byte programming time is a fast 50
µs.
The
end of a program cycle can be optionally detected by the
DATA polling feature. Once the end of a byte program
cycle has been detected, a new access for a read or pro-
gram can begin. The typical number of program and erase
cycles is in excess of 10,000 cycles.
The device is erased by executing the erase command
sequence; the device internally controls the erase opera-
tions. There are two 8K byte parameter block sections and
two main memory blocks.
The device has the capability to protect the data in the boot
block; this feature is enabled by a command sequence.
The 16K-byte boot block section includes a reprogramming
lock out feature to provide data integrity. The boot sector is
designed to contain user secure code, and when the fea-
ture is enabled, the boot sector is protected from being
reprogrammed.
In the AT49F002NT, once the boot block programming
lockout feature is enabled, the contents of the boot block
are permanent and cannot be changed. In the AT49F002T,
once the boot block programming lockout feature is
enabled, the contents of the boot block cannot be changed
with input voltage levels of 5.5 volts or less.
Block Diagram
DATA INPUTS/OUTPUTS
I/O7 - I/O0
V
CC
GND
OE
WE
CE
RESET
8
INPUT/OUTPUT
BUFFERS
PROGRAM
DATA LATCHES
Y-GATING
3FFFF
X DECODER
BOOT BLOCK
(16K BYTES)
PARAMETER
BLOCK 1
(8K BYTES)
PARAMETER
BLOCK 2
(8K BYTES)
MAIN MEMORY
BLOCK 1
(96K BYTES)
MAIN MEMORY
BLOCK 2
(128K BYTES)
3C000
3BFFF
CONTROL
LOGIC
Y DECODER
ADDRESS
INPUTS
3A000
39FFF
38000
37FFF
20000
1FFFF
00000
2
AT49F002(N)T
ATMEL [ ATMEL CORPORATION ]
