28F008SA-L Просмотр технического описания (PDF) - Intel

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28F008SA-L

8-MBIT (1 MBIT x 8) FLASHFILE™ MEMORY

Intel 

28F008SA-L

PRINCIPLES OF OPERATION

The 28F008SA-L includes on-chip write automation

to manage write and erase functions The Write

State Machine allows for 100% TTL-level control

inputs fixed power supplies during block erasure

and byte write and minimal processor overhead with

RAM-like interface timings

After initial device powerup or after return from

deep powerdown mode (see Bus Operations) the

28F008SA-L functions as a read-only memory Ma-

nipulation of external memory-control pins allow ar-

ray read standby and output disable operations

Both Status Register and intelligent identifiers can

also be accessed through the Command User Inter-

face when VPP e VPPL

This same subset of operations is also available

when high voltage is applied to the VPP pin In addi-

tion high voltage on VPP enables successful block

erasure and byte writing of the device All functions

associated with altering memory contents byte

write block erase status and intelligent identifier

are accessed via the Command User Interface and

verified thru the Status Register

Commands are written using standard microproces-

sor write timings Command User Interface contents

serve as input to the WSM which controls the block

erase and byte write circuitry Write cycles also inter-

nally latch addresses and data needed for byte write

or block erase operations With the appropriate com-

mand written to the register standard microproces-

sor read timings output array data access the Intelli-

gent Identifier codes or output byte write and block

erase status for verification

Interface software to initiate and poll progress of in-

ternal byte write and block erase can be stored in

any of the 28F008SA-L blocks This code is copied

to and executed from system RAM during actual

flash memory update After successful completion of

byte write and or block erase code data reads from

the 28F008SA-L are again possible via the Read Ar-

ray command Erase suspend resume capability al-

lows system software to suspend block erase to

read data and execute code from any other block

FFFFF

F0000

EFFFF

E0000

DFFFF

D0000

CFFFF

C0000

BFFFF

B0000

AFFFF

A0000

9FFFF

90000

8FFFF

80000

7FFFF

70000

6FFFF

60000

5FFFF

50000

4FFFF

40000

3FFFF

30000

2FFFF

20000

1FFFF

10000

0FFFF

00000

64-Kbyte Block

64-Kbyte Block

64-Kbyte Block

64-Kbyte Block

64-byte Block

64-Kbyte Block

64-Kbyte Block

64-Kbyte Block

64-Kbyte Block

64-Kbyte Block

64-Kbyte Block

64-Kbyte Block

64-Kbyte Block

64-Kbyte Block

64-Kbyte Block

64-Kbyte Block

Figure 6 Memory Map

Command User Interface and Write

Automation

An on-chip state machine controls block erase and

byte write freeing the system processor for other

tasks After receiving the Erase Setup and Erase

Confirm commands the state machine controls

block pre-conditioning and erase returning progress

via the Status Register and RY BY output Byte

write is similarly controlled after destination address

and expected data are supplied The program and

erase algorithms of past Intel flash memories are

now regulated by the state machine including pulse

repetition where required and internal verification

and margining of data

8

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