A29L400A Series
General Description
The A29L400A is an 4Mbit, 3.0 volt-only Flash memory
organized as 524,288 bytes of 8 bits or 262,144 words of 16
bits each. The 8 bits of data appear on I/O
0
- I/O
7
; the 16 bits
of data appear on I/O
0
~I/O
15
. The A29L400A is offered in 48-
ball TFBGA, 44-pin SOP and 48-Pin TSOP packages. This
device is designed to be programmed in-system with the
standard system 3.0 volt VCC supply. Additional 12.0 volt
VPP is not required for in-system write or erase operations.
However, the A29L400A can also be programmed in
standard EPROM programmers.
The A29L400A has the first toggle bit, I/O
6
, which indicates
whether an Embedded Program or Erase is in progress, or it
is in the Erase Suspend. Besides the I/O
6
toggle bit, the
A29L400A has a second toggle bit, I/O
2
, to indicate whether
the addressed sector is being selected for erase. The
A29L400A also offers the ability to program in the Erase
Suspend mode. The standard A29L400A offers access times
of 70 and 90ns, allowing high-speed microprocessors to
operate without wait states. To eliminate bus contention the
device has separate chip enable (
CE
), write enable (
WE
)
and output enable (
OE
) controls.
The device requires only a single 3.0 volt power supply for
both read and write functions. Internally generated and
regulated voltages are provided for the program and erase
operations.
The A29L400A is entirely software command set compatible
with the JEDEC single-power-supply Flash standard.
Commands are written to the command register using
standard microprocessor write timings. Register contents
serve as input to an internal state-machine that controls the
erase and programming circuitry. Write cycles also internally
latch addresses and data needed for the programming and
erase operations. Reading data out of the device is similar to
reading from other Flash or EPROM devices.
Device programming occurs by writing the proper program
command sequence. This initiates the Embedded Program
algorithm - an internal algorithm that automatically times the
program pulse widths and verifies proper program margin.
Device erasure occurs by executing the proper erase
command sequence. This initiates the Embedded Erase
algorithm - an internal algorithm that automatically
preprograms the array (if it is not already programmed)
before executing the erase operation. During erase, the
device automatically times the erase pulse widths and
verifies proper erase margin. The Unlock Bypass mode
facilitates faster programming times by requiring only two
write cycles to program data instead of four.
The host system can detect whether a program or erase
operation is complete by observing the RY /
BY
pin, or by
reading the I/O
7
(
Data
Polling) and I/O
6
(toggle) status bits.
After a program or erase cycle has been completed, the
device is ready to read array data or accept another
command.
The sector erase architecture allows memory sectors to be
erased and reprogrammed without affecting the data contents
of other sectors. The A29L400A is fully erased when shipped
from the factory.
The hardware sector protection feature disables operations
for both program and erase in any combination of the
sectors of memory. This can be achieved via programming
equipment.
The Erase Suspend/Erase Resume feature enables the user
to put erase on hold for any period of time to read data from,
or program data to, any other sector that is not selected for
erasure. True background erase can thus be achieved.
The hardware
RESET
pin terminates any operation in
progress and resets the internal state machine to reading
array data. The
RESET
pin may be tied to the system reset
circuitry. A system reset would thus also reset the device,
enabling the system microprocessor to read the boot-up
firmware from the Flash memory.
The device offers two power-saving features. When
addresses have been stable for a specified amount of time,
the device enters the automatic sleep mode. The system can
also place the device into the standby mode. Power
consumption is greatly reduced in both these modes.
PRELIMINARY
(July, 2005, Version 0.0)
2
AMIC Technology, Corp.
AMICC [ AMIC TECHNOLOGY ]
