M28F008 datasheet(7/28 Pages) INTEL

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M28F008

Table 2 Bus Operations

Mode

Notes

VPP

DQ0–7

RYBY

Read

1 2 3

VIH

VIL

VIH

DOUT

Output Disable

VIH

VIL

VIH

High Z

Standby

VIH

High Z

PowerDown

VIL

High Z

VOH

Intelligent Identifier (Mfr)

VIH

VIL

VIH

VIL

89H

VOH

Intelligent Identifier (Device)

VIH

VIL

VIH

A2H

VOH

Write

3 4 5

VIH

VIL

VIH

VIL

DIN

NOTES

1 Refer to DC Characteristics When VPP e VPPL memory contents can be read but not written or erased

2 X can be VIL or VIH for control pins and addresses and VPPL or VPPH for VPP See DC Characteristics for VPPL and VPPH

voltages

3 RYBY is VOL when the Write State Machine is executing internal block erase or byte write algorithms It is VOH when the

WSM is not busy in Erase Suspend mode or deep powerdown mode

4 Command writes involving block erase or byte write are only successfully executed when VPP e VPPH

5 Refer to Table 3 for valid DIN during a write operation

must be logically active to obtain data at the outputs

Chip Enable (CE) is the device selection control and

when active enables the selected memory device

Output Enable (OE) is the data inputoutput (DQ0–

DQ7) direction control and when active drives data

from the selected memory onto the IO bus RP and

WE must also be at VIH Figure 8 illustrates read bus

cycle waveforms

Output Disable

With OE at a logic-high level (VIH) the device out-

puts are disabled

Output pins (DQ0–DQ7) are

placed in a high-impedance state

Standby

CE at a logic-high level (VIH) places the M28F008 in

standby mode Standby operation disables much of

the M28F008’s circuitry and substantially reduces

device power consumption The outputs (DQ0–DQ7)

are placed in a high-impedence state independent of

the status of OE If the M28F008 is deselected dur-

ing block erase or byte write the device will continue

functioning and consuming normal active power until

the operation completes

Deep Power-Down

The M28F008 offers a deep powerdown feature en-

tered when RP is at VIL Current draw thru VCC is

100 mA maximum in deep powerdown mode with

current draw through VPP 20 mA maximum During

read modes RP at a logic-low level (VIL) deselects

the memory places output drivers in a high-impe-

dence state and turns off all internal circuits The

M28F008 requires time tPHQV (see AC Characteris-

tics-Read-Only Operations) after return from power-

down until initial memory access outputs are valid

After this wakeup interval normal operation is re-

stored The Command User Interface is reset to

Read Array mode and the upper 5 bits of the Status

normal operation

During block erase or byte write modes RP at a log-

ic-low level (VIL) will abort either operation Memory

contents of the block being altered are no longer

valid as the data will be partially written or erased

Time tPHWL after RP goes to logic-high (VIH) is re-

quired before another command can be written

Intelligent Identifier Operation

The intelligent identifier operation outputs the manu-

facturer code 89H and the device code A2H for

the M28F008 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 ad-

dress location 00000H outputs the manufacturer

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

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

have high voltage applied to VPP to read the intelli-

gent identifier from the Command User Interface

M28F008 Datasheet(PDF) 7 Page - Intel Corporation

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