8

V29LC51000 Rev. 0.4 October 2000

MOSEL VITELIC

V29LC51000

FUNCTIONAL DESCRIPTION

Read Cycle

A read cycle is performed by holding both CE

and OE signals LOW. Data Out becomes valid only

when these conditions are met. During a read cycle

WE must be HIGH prior to CE and OE going LOW.

WE must remain HIGH during the read operation

for the read to complete (see Table 1).

Output Disable

Returning OE or CE HIGH, whichever occurs first

will terminate the read operation and place the l/O

pins in the HIGH-Z state.

Standby

The device will enter standby mode when the CE

signal is HIGH. The l/O pins are placed in the

HIGH-Z, independent of the OE signal.

Command Sequence

The V29LC51000 does not provide the “reset”

feature to return the chip to its normal state when

an incomplete command sequence or an

interruption has happened. In this case, normal

operation (Read Mode) can be restored by issuing

a “non-existent” command sequence, for example

Address: 5555H, Data FFH.

Byte Program Cycle

The V29LC51000 is programmed on a byte-by-

byte basis. The byte program operation is initiated

by using a specific four-bus-cycle sequence: two

unlock program cycles, a program setup command

and program data program cycles (see Table 2).

During the byte program cycle, addresses are

latched on the falling edge of either CE or WE,

whichever is last. Data is latched on the rising edge

of CE or WE, whichever is first. The byte program

cycle can be CE controlled or WE controlled.

Sector Erase Cycle

The V29LC51000 features a sector erase

operation which allows each sector to be erased

and reprogrammed without affecting data stored in

other sectors. Sector erase operation is initiated by

using a specific six-bus-cycle sequence: Two

unlock program cycles, a setup command, two

additional unlock program cycles, and the sector

erase command (see Table 2). A sector must be

first erased before it can be reprogrammed. While

in the internal erase mode, the device ignores any

program attempt into the device. Sector erase is

completed in 10ms max. The V29LC51000 is

shipped with pre-erased sectors (all bits = 1).

512

512

•

•

•

512

512

V29LC51001

00000H

L51001-13

Table 1. Operation Modes Decoding

NOTES:

1.

2.

PD: The data at the byte address to be programmed.

Decoding Mode

CE

OE

WE

I/O

Read

READ

Byte Write

PD

Standby

XXXXX

HIGH-Z

Output Disable

X

X

X

HIGH-Z