28F008SA

Deep Power-Down

The 28F008SA offers a deep power-down feature

entered when RP

is 020 mA typical in deep power-down mode with

read modes

RP -low deselects the memory

places output drivers in a high-impedence state and

turns off all internal circuits The 28F008SA requires

erations) after return from powerdown until initial

memory access outputs are valid After this wakeup

interval normal operation is restored The Com-

mand User Interface is reset to Read Array and the

upper 5 bits of the Status Register are cleared to

value 10000 upon return to normal operation

During block erase or byte write modes RP

low

will abort either operation Memory contents of the

block being altered are no longer valid as the data

RP

other command can be written

This use of RP

during system reset is important

with automated writeerase devices When the sys-

tem comes out of reset it expects to read from the

flash memory Automated flash memories provide

status information when accessed during write

erase modes If a CPU reset occurs with no flash

memory reset proper CPU initialization would not

occur because the flash memory would be providing

the status information instead of array data Intel’s

Flash Memories allow proper CPU initialization fol-

lowing a system reset through the use of the RP

input In this application RP

is controlled by the

same RESET

signal that resets the system CPU

Intelligent Identifier Operation

The intelligent identifier operation outputs the manu-

facturer code 89H and the device code A2H for

the 28F008SA The system CPU can then automati-

cally match the device with its proper block erase

and byte write algorithms

The manufacturer- and device-codes are read via

the Command User Interface Following a write of

90H to the Command User Interface a read from

address location 00000H outputs the manufacturer

code (89H) A read from address 00001H outputs

the device code (A2H) It is not necessary to have

identifiers from the Command User Interface

Table 3 Command Definitions

Command

Cycles

Req’d

Bus

Notes

First Bus Cycle

Second Bus Cycle

Operation Address Data Operation Address Data

Read ArrayReset

1

1

Write

X

FFH

Intelligent Identifier

3

2 3 4

Write

X

90H

Read

IA

IID

Read Status Register

2

3

Write

X

70H

Read

X

SRD

Clear Status Register

1

Write

X

50H

Erase SetupErase Confirm

2

2

Write

BA

20H

Write

BA

D0H

Erase SuspendErase Resume

2

Write

X

B0H

Write

X

D0H

Byte Write SetupWrite

2

2 3 5

Write

WA

40H

Write

WA

WD

Alternate Byte Write SetupWrite

2

2 3 5

Write

WA

10H

Write

WA

WD

NOTES

1 Bus operations are defined in Table 2

4 Following the Intelligent Identifier command two read operations access manufacture and device codes

5 Either 40H or 10H are recognized by the WSM as the Byte Write Setup command

6 Commands other than those shown above are reserved by Intel for future device implementations and should not be

used

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