8

Am29F400AT/Am29F400AB

PRELIMINARY

Table 1.

Table 2.

Legend:

L = logic 0, H = logic 1, X = Don’t Care. See Characteristics for voltage levels.

Notes:

1. Manufacturer and device codes may also be accessed via a command register write sequence. Refer to Table 4.

2. Refer to the section on Sector Protection.

Read Mode

The Am29F400A has two control functions which must

be satisfied in order to obtain data at the outputs. CE is

the power control and should be used for device selec-

tion. OE is the output control and should be used to

gate data to the output pins if a device is selected.

stable addresses to valid output data. The chip enable

and stable CE to valid data at the output pins.

The output enable access time is the delay from the

falling edge of OE to valid data at the output pins (as-

suming the addresses have been stable for at least

Standby Mode

There are two ways to implement the standby mode on

the Am29F400A device, both using the CE pin.

A CMOS standby mode is achieved with the CE input

typically reduced to less than 5

µA. A TTL standby

this condition the current is typically reduced to 1 mA.

In the standby mode the outputs are in the high imped-

ance state, independent of the OE input.

Operation

CE

OE

WE

A0

A1

A6

A9

DQ0–DQ15

RESET

Autoselect, AMD Manuf. Code (Note 1)

L

L

H

L

L

L

Code

H

Autoselect Device Code (Note 1)

L

L

H

H

L

L

Code

H

Read

L

L

H

A0

A1

A6

A9

H

Standby

H

XXXXXX

HIGH Z

H

Output Disable

L

H

H

XXXX

HIGH Z

H

Write

L

H

L

A0

A1

A6

A9

H

Verify Sector Protect (Note 2)

L

LHLHL

Code

H

Temporary Sector Unprotect

XXXXXXX

X

Hardware Reset

XXXXXXX

HIGH Z

L

Operation

CE

OE

WE

A0

A1

A6

A9

DQ0–DQ7 DQ8–DQ15 RESET

Autoselect, AMD Manuf. Code

(Note 1)

LL

H

LLL

Code

HIGH Z

H

Autoselect Device Code (Note 1)

L

L

H

H

L

L

Code

HIGH Z

H

Read

L

L

H

A0

A1

A6

A9

HIGH Z

H

Standby

H

XXXXXX

HIGH Z

HIGH Z

H

Output Disable

L

H

H

XXXX

HIGH Z

HIGH Z

H

Write

L

H

L

A0

A1

A6

A9

HIGH Z

H

Verify Sector Protect (Note 2)

L

LHLHL

Code

HIGH Z

H

Temporary Sector Unprotect

XXXXXXX

X

HIGH Z

Hardware Reset

XXXXXXX

HIGH Z

HIGH Z

L