To allow for simple in-system reprogrammability, the

AT29BV010A does not require high input voltages for pro-

gramming. The device can be operated with a single 2.7V

to 3.6V supply. Reading data out of the device is similar to

r eadi ng f r om a n EPROM . Re pr o g r a mm in g th e

AT29BV010A is performed on a sector basis; 128-bytes of

data are loaded into the device and then simultaneously

programmed.

During a reprogram cycle, the address locations and 128-

bytes of data are captured at microprocessor speed and

internally latched, freeing the address and data bus for

other operations. Following the initiation of a program cy-

cle, the device will automatically erase the sector and then

program the latched data using an internal control timer.

The end of a program cycle can be detected by DATA poll-

ing of I/O7. Once the end of a program cycle has been

detected, a new access for a read or program can begin.

Description (Continued)

Device Operation

READ:

The AT29BV010A 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

contention.

SOFTWARE DATA PROTECTION PROGRAMMING:

The AT29BV010A has 1024 individual sectors, each 128-

bytes. Using the software data protection feature, byte

loads are used to enter the 128-bytes of a sector to be

programmed. The AT29BV010A can only be programmed

or reprogrammed using the software data protection fea-

ture. The device is programmed on a sector basis. If a byte

of data within the sector is to be changed, data for the en-

tire 128-byte sector must be loaded into the device. The

data in any byte that is not loaded during the programming

of its sector will be indeterminate. The AT29BV010A auto-

matically does a sector erase prior to loading the data into

the sector. An erase command is not required.

Software data protection protects the device from inadver-

tent programming. A series of three program commands

to specific addresses with specific data must be presented

to the device before programming may occur. The same

three program commands must begin each program op-

eration. All software program commands must obey the

sector program timing specifications. Power transitions

will not reset the software data protection feature, however

(continued)

Block Diagram

the software feature will guard against inadvertent pro-

gram cycles during power transitions.

Any attempt to write to the device without the 3-byte com-

mand sequence will start the internal write timers. No data

will be written to the device; however, for the duration of

After the software data protection’s 3-byte command code

is given, a byte load is performed 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.

The 128-bytes of data must be loaded into each sector.

Any byte that is not loaded during the programming of its

sector will be indeterminate. Once the bytes of a sector

are loaded into the device, they are simultaneously pro-

grammed during the internal programming period. After

the first data byte has been loaded into the device, suc-

cessive bytes are entered in the same manner. Each new

byte to be programmed must have its high to low transition

on WE (or CE) within 150

µs of the low to high transition of

WE (or CE) of the preceding byte. If a high to low transition

is not detected within 150

µs of the last low to high transi-

tion, the load period will end and the internal programming

period will start. A7 to A16 specify the sector address. The

sector address must be valid during each high to low tran-

sition of WE (or CE). A0 to A6 specify the byte address

4-4

AT29BV010A