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The AS29LV800 is an 8 megabit, 3.0 volt Flash memory organized as 1 Megabyte of 8 bits/512Kbytes of 16 bits each. For
flex ible e rase and program capabili ty, the 8 megabit s of data is divided int o ninetee n sectors : one 16K , two 8K, one 3 2K, and
fifteen 64k byte sectors; or one 8K, two 4K, one 16K, and fifteen 32K w ord sectors. The ×8 data appears on DQ0–DQ7; the ×16
data appears on DQ0–DQ15. The AS29LV800 is offered in JEDEC standard 48-pin TSOP and 44-pin SO (availability TBD)
packages. This device is desi g ned to be progr ammed a nd erased in -system with a single 3. 0V VCC supply. The device can also be
reprogrammed in standard EPROM programmers.
The AS29LV800 offers access times of 70/80/90/120 ns, allowing 0-wait state operation of high speed microprocessors. To
eliminate bus contention the device has separate chip enable (CE), wr ite enable (WE) , and output en able (OE ) controls. Word
mode (×16 output) is selected by BYTE = high. Byte mode (×8 output) is selected by BYTE = l ow.
The AS29LV800 is fully compatible with the JEDEC single power supply Flash standard. Write commands are sent to the
command register using standard microprocessor write timings. An internal state-machine uses register contents to control the
erase and programming circuitry. Write cycles also internally latch addresses and data needed for the programming and erase
ope rations. Rea d data from the device occu rs in the sa me man ner as oth er Fla sh or EPROM device s. Use the progr am com mand
sequence to invoke the automated on-chip programming algorithm that automatically times the program pulse widths and
verif ies pro per cell margin. Use the era se comman d sequ ence to invok e th e auto mat ed on -chip erase algorith m tha t pr epr og rams
the sector (if it is not already programmed before executing the erase operation), times the erase pulse widths, and verifies
proper cell margin.
Boot sector architecture enables the system to boot from either the top (AS29LV800T) or the bottom (AS29LV800B) sector.
Sector erase architecture allows specified sectors of memory to be erased and reprogrammed without altering data in other
sectors. A sector typically erases and verifies within 1.0 seconds. Hardware sector protection disables both program and erase
operations in all, or any combination of, the nineteen sectors. The device provides true background erase with Erase Suspend,
which puts erase op era ti ons on h old t o ei ther r ead da ta f ro m, or p ro gram dat a to , a se ctor th at is not bein g eras ed . The chip e rase
command will auto maticall y erase all unprot ected sectors.
A factory shi pp ed A S2 9LV800 is ful ly erased (a ll bits = 1) . The pro g ram min g op er ation set s bits to 0 . Data i s prog ra mme d in to
the array one byte at a time in any sequence and across sector boundar ies. A sector must be erased to change bits from 0 to 1.
Erase returns all bytes in a sector to the erased state (all bits = 1). Each sector is erased individually with no effect on other
sectors.
The device fe atures sing le 3.0V power supp ly operation for Read, Write, and Erase functions. Internally gener ated and regulated
voltages are provided for the Program and Erase operations. A low VCC detector automatically inhibits write operations during
power t ranstit ions. The RY/B Y pin, DATA po lling of DQ7, or toggle bit (D Q6) may be us ed to de tect end of progra m or e rase
operations. The device automatically resets to the read mode after program/erase operations are completed. DQ2 indicates
which sectors ar e being erased.
The AS29LV800 resists accidental erasure or spurious programming signals resulting from power transitions. Control register
architecture permits alteration of memory contents only after successful completion of specific command sequences. During
power up, the device is set to read mode with all program/erase commands disabled when VCC is less than VLKO (lockout
vol ta ge ). Th e com mand r egi sters are not affected b y noise pul ses o f les s th an 5 ns on OE, CE, or WE. To initia te write command s,
CE and WE must be logical zero and OE a logical 1.
When the device’s hardware RESET pin is driven low, any program/erase operation in progress is terminated and the internal
state machine is reset to read mode. If the RESET pin is tied to the system reset circuitry and a system reset occurs during an
automated on-chip program/erase algorithm, data in address locations being operated on may become corr upted and requires
rewriting. Resetting the device enables the system’s microprocessor to read boot-up firmware from the Flash memory.
The AS29LV800 uses Fowler-Nordheim tunnelling to electrically erase all bits within a sector simultaneously. Bytes are
programmed one at a time using EPROM programming mechanism of hot electron injection.