 2004 Microchip Technology Inc.

DS11001N-page 5

27C256

FIGURE 1-2:

PROGRAMMING WAVEFORMS

TABLE 1-6:

MODES

Operation Mode

CE

OE

A9

O0 - O7

Read

Program

Program Verify

Program Inhibit

X

High Z

Standby

X

High Z

Output Disable

X

High Z

Identity

Identity Code

X = Don’t Care

13.0V(2)

5.0V

6.5V(2)

5.0V

Address

Data

CE

OE

Address Stable

(1)

(1)

Program

Data Stable

Data Out Valid

Verify

Notes:

(1)

(2)

High Z

1.2

Read Mode

(See Timing Diagrams and AC Characteristics)

Read Mode is accessed when:

a)

the CE pin is low to power up (enable) the chip

b)

the OE pin is low to gate the data to the output

pins

For Read operations, if the addresses are stable, the