AS29LV016 Просмотр технического описания (PDF) - Austin Semiconductor

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AS29LV016

16 Megabit (2M x 8-Bit / 1M x 16-Bit) CMOS 3.0 Volt-Only Boot Sector Flash Memory

Austin Semiconductor 

COTS PEM

BOOT SECTOR FLASH

Austin Semiconductor, Inc.

AS29LV016

WORD/BYTE PROGRAM COMMAND

SEQUENCE

The system may program the device by word or byte,

depending on the state of the BYTE# pin. Programming

is a four-bus-cycle operation. The program command

sequence is initiated by writing two unlock write cycles,

followed by the program set-up command. The program

address and data are written next, which in turn initiate

the Embedded Program algorithm. The system is not

required to provide further controls or timings. The device

automatically generates the program pulses and verifies

the programmed cell margin. Table 9 on page 21 shows

the address and data requirements for the byte program

command sequence.

When the Embedded Program algorithm is complete, the

device then returns to reading array data and addresses

are no longer latched. The system can determine the

status of the program operation by using DQ7, DQ6, or

RY/BY#. See Write Operation Status on page 22 for

information on these status bits.

This mode dispenses with the initial two unlock cycles

required in the standard program command sequence,

resulting in faster total programming time. Table 9 on

page 21 shows the requirements for the command

sequence.

During the unlock bypass mode, only the Unlock Bypass

Program and Unlock Bypass Reset commands are valid.

To exit the unlock bypass mode, the system must issue

the two-cycle unlock bypass reset command sequence.

The first cycle must contain the data 90h; the second

cycle the data 00h. Addresses are don’t care for both

cycles. The device then returns to reading array data.

Figure 3 illustrates the algorithm for the program operation.

See Erase / Program Operations on page 32 for

parameters, and to Figure 16, on page 33 for timing

diagrams.

START

Any commands written to the device during the Embedded

Program Algorithm are ignored. Note that a hardware

reset immediately terminates the programming operation.

The Byte Program command sequence should be

reinitiated once the device has reset to reading array data,

to ensure data integrity.

Programming is allowed in any sequence and across

sector boundaries. A bit cannot be programmed from

a 0 back to a 1. Attempting to do so may halt the

operation and set DQ5 to 1, or cause the Data# Polling

algorithm to indicate the operation was successful.

However, a succeeding read will show that the data is

still 0. Only erase operations can convert a 0 to a 1.

Write Program

Command Sequence

Embedded

Program

algorithm

in progress

Data Poll

from System

Verify Data?

No

Yes

UNLOCK BYPASS COMMAND SEQUENCE

The unlock bypass feature allows the system to program

bytes or words to the device faster than using the standard

program command sequence. The unlock bypass

command sequence is initiated by first writing two unlock

cycles. This is followed by a third write cycle containing

the unlock bypass command, 20h. The device then enters

the unlock bypass mode. A two-cycle unlock bypass

program command sequence is all that is required to

program in this mode. The first cycle in this sequence

contains the unlock bypass program command, A0h; the

second cycle contains the program address and data.

Additional data is programmed in the same manner.

Increment Address

No

Last Address?

Yes

Programming

Completed

Note: See Table 9 on page 21 for program command

sequence.

Figure 3. Program Operation

AS29LV016

Rev. 2.1 10/08

18

Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.

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