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MX29LV040

4M-BIT [512K x 8] CMOS SINGLE VOLTAGE 3V ONLY EQUAL SECTOR FLASH MEMORY

Macronix International 

MX29LV040

REQUIREMENTS FOR READING ARRAY

DATA

To read array data from the outputs, the system must

drive the CE and OE pins to VIL. CE is the power control

and selects the device. OE is the output control and gates

array data to the output pins. WE should remain at VIH.

The internal state machine is set for reading array data

upon device power-up, or after a hardware reset. This

ensures that no spurious alteration of the memory contect

occurs during the power transition. No command is

necessary in this mode to obtain array data. Standard

microprocessor read cycles that assert valid address on

the device address inputs produce valid data on the device

data outputs. The device remains enabled for read access

until the command register contents are altered.

WRITE COMMANDS/COMMAND

SEQUENCES

To program data to the device or erase sectors of memory

, the sysytem must drive WE and CE to VIL, and OE to

VIH.

The device features an Unlock Bypass mode to facilitate

faster programming. Once the device enters the Unlock

Bypass mode, only two write cycles are required to

program a byte, instead of four. The "byte Program

Command Sequence" section has details on

programming data to the device using both standard and

Unlock Bypass command sequences.

An erase operation can erase one sector, multiple sectors

, or the entire device. Table indicates the address space

that each sector occupies. A "sector address" consists

of the address bits required to uniquely select a sector.

The "Writing specific address and data commands or

sequences into the command register initiates device

operations. Table 3 defines the valid register command

sequences. Writing incorrect address and data values or

writing them in the improper sequence resets the device

to reading array data."section has details on erasing a

sector or the entire chip, or suspending/resuming the erase

operation.

After the system writes the autoselect command

sequence, the device enters the autoselect mode. The

system can then read autoselect codes from the internal

reqister (which is separate from the memory array) on

Q7-Q0. Standard read cycle timings apply in this mode.

Refer to the Autoselect Mode and Autoselect Command

Sequence section for more information.

ICC2 in the DC Characteristics table represents the

active current specification for the write mode. The "AC

Characteristics" section contains timing specification

table and timing diagrams for write operations.

STANDBY MODE

When the sysytem is not reading or writing to the de-

vice, it can place the device in the standby mode. In this

mode, current consumption is greatly reduced, and the

outputs are placed in the high impedance state, inde-

pendent of the OE input.

The device enters the CMOS standby mode when the

CE pin is both held at VCC±0.3V. (Note that this is a

more restricted voltage range than VIH.) If CE is held at

VIH, but not within VCC±0.3V, the device will be in the

standby mode, but the standby currect will be greater.

The device requires standard access time (tCE) for read

access when the device is in either of these standby

modes, before itis ready to read data.

If the device is deselected during erasure or program-

ming, the device draws active current until the operation

is completed.

ICC3 in the DC Characteristicstable represents the

standby current specification.

OUTPUT DISABLE

With the OE input at a logic high level (VIH), output from

the devices are disabled. This will cause the output pins

to be in a high impedance state.

READ/RESET COMMAND

The read or reset operation is initiated by writing the

read/reset command sequence into the command reg-

ister. Microprocessor read cycles retrieve array data.

The device remains enabled for reads until the command

register contents are altered.

If program-fail or erase-fail happen, the write of F0H will

reset the device to abort the operation. A valid com-

mand must then be written to place the device in the

desired state.

P/N:PM0722

REV. 0.7, JUL. 12, 2001

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