M58LW64D datasheet(12/50 Pages) STMICROELECTRONICS

12 / 50 page

M58LW064D

12/50

BUS OPERATIONS

There are five standard bus operations that control

the device. These are Bus Read, Bus Write, Out-

put Disable, Power-Down and Standby. See Table

3., Bus Operations, for a summary.

Typically glitches of less than 5ns on Chip Enable

or Write Enable are ignored by the memory and do

not affect Bus Write operations.

Bus Read. Bus Read operations are used to out-

put the contents of the Memory Array, the Elec-

tronic Signature, the Status Register, the Common

Flash Interface and the Block Protection Status.

A valid bus operation involves setting the desired

address on the Address inputs, enabling the de-

vice (refer to Table 2., Device Enable), applying a

Low signal, VIL, to Output Enable and keeping

Write Enable High, VIH. The data read depends on

the previous command written to the memory (see

Command Interface section).

See Figures 9 and 10 Read AC Waveforms, and

Tables 15 and 16 Read AC Characteristics, for de-

tails of when the output becomes valid.

Bus Write. Bus Write operations write Com-

mands to the memory or latch addresses and input

data to be programmed.

A valid Bus Write operation begins by setting the

desired address on the Address Inputs and en-

abling the device (refer to Chip Enable section).

The Address Inputs are latched by the Command

Interface on the rising edge of Write Enable or the

first edge of E0, E1 or E2 that disables the device

(refer to Table 2., Device Enable).

The Data Input/Outputs are latched by the Com-

mand Interface on the rising edge of Write Enable

or the first edge of E0, E1 or E2 that disable the de-

vice whichever occurs first. Output Enable must

remain High, VIH, during the Bus Write operation.

See Figures 11 and 12, Write AC Waveforms, and

Tables 17 and 18, Write and Chip Enable Con-

trolled Write AC Characteristics, for details of the

timing requirements.

Output Disable. The Data Inputs/Outputs are

high impedance when the Output Enable is at VIH.

Power-Down. The memory is in Power-Down

mode when Reset/Power-Down, RP, is Low. The

power consumption is reduced to the Power-Down

level, IDD2, and the outputs are high impedance,

independent of Chip Enable, Output Enable or

Write Enable.

Standby. Standby disables most of the internal

circuitry, allowing a substantial reduction of the

current consumption. The memory is in standby

when Chip Enable is at VIH. The power consump-

tion is reduced to the standby level IDD1 and the

outputs are set to high impedance, independently

from the Output Enable or Write Enable inputs.

If Chip Enable switches to VIH during a program or

erase operation, the device enters Standby mode

when finished.

Table 3. Bus Operations

Note: 1. DQ8-DQ15 are High Z in x8 mode.

2. X = Don’t Care VIL or VIH.

Operation

E0, E1

or E2

A1-A22 (x16)

A0-A22 (x8)

DQ0-DQ15 (x16)

DQ0-DQ7 (x8)(1)

Bus Read

VIL

VIH

Address

Data Output

Bus Write

VIL

VIH

VIL

VIH

Address

Data Input

Output Disable

VIL

VIH

XHigh Z

Power-Down

VIL

XHigh Z

Standby

VIH

XHigh Z

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