M68AW127B datasheet(11/20 Pages) STMICROELECTRONICS

11 / 20 page

11/20

M68AW127B

Write Mode

The M68AW127B is in the Write mode whenever

the W and E1 pins are Low and the E2 pin is High.

Either the Chip Enable input (E1) or the Write En-

able input (W) must be de-asserted during Ad-

dress transitions for subsequent write cycles.

Write begins with the concurrence of E1 being ac-

tive with W low. Therefore, address setup time is

referenced to Write Enable and Chip Enable as

tAVWL and tAVEH, respectively, and is determined

by the latter occurring edge.

The Write cycle can be terminated by the earlier

rising edge of E1, or W.

If the Output is enabled (E1 = Low, E2 = High and

G = Low), then W will return the outputs to high im-

pedance within tWLQZ of its falling edge. Care must

be taken to avoid bus contention in this type of op-

eration. Data input must be valid for tDVWH before

the rising edge of Write Enable, or for tDVEH before

the rising edge of E1, whichever occurs first, and

remain valid for tWHDX or tEHDX.

Figure 11. Write Enable Controlled, Write AC Waveforms

AI05478

tAVAV

tWHAX

tDVWH

DATA INPUT

A0-A16

DQ0-DQ7

VALID

tAVWH

tAVEL

tWLWH

tAVWL

tWLQZ

tWHDX

tWHQX

tELWH

M68AW127B 데이터시트(PDF) 11 Page - STMicroelectronics