Rainbow Electronics AT29LV010A - Manual (Page 2)

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AT29LV010A
0520D–FLASH–05/02
To allow for simple in-system reprogrammability, the AT29LV010A does not require high
input voltages for programming. Three-volt-only commands determine the operation of
the device. Reading data out of the device is similar to reading from an EPROM. Repro-
gramming the AT29LV010A 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 cycle, 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 polling of I/O7. Once the end of a pro-
gram cycle has been detected, a new access for a read or program can begin.
Block Diagram
Device Operation
READ: The AT29LV010A 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 AT29LV010A has 1024 indi-
vidual 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 AT29LV010A can
only be programmed or reprogrammed using the software data protection feature. The
device is programmed on a sector basis. If a byte of data within the sector is to be
changed, data for the entire 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 AT29LV010A automatically 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 inadvertent 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 operation. All software program commands must obey the sector
program timing specifications. Power transitions will not reset the software data protec-
tion feature; however, the software feature will guard against inadvertent program cycles
during power transitions.
Any attempt to write to the device without the 3-byte command sequence will start the
internal write timers. No data will be written to the device; however, for the duration of
t
WC
, a read operation will effectively be a polling operation.