6.42

71321SA/LA and 71421SA/LA

High Speed 2K x 8 Dual-Port Static RAM with Interrupts

Industrial and Commercial Temperature Ranges

15

Truth Table III — Address BUSY Arbitration

Truth Table I. Non-Contention Read/Write Control(4)

NOTES:

1. Pins BUSYL and BUSYR are both outputs for IDT71321 (Master). Both are inputs for IDT71421 (Slave). BUSYX outputs on the IDT71321 are open drain, not push-

pull outputs. On slaves the BUSYX input internally inhibits writes.

2. 'L' if the inputs to the opposite port were stable prior to the address and enable inputs of this port. 'H' if the inputs to the opposite port became stable after the address

and enable inputs of this port. If tAPS is not met, either BUSYL or BUSYR = LOW will result. BUSYL and BUSYR outputs can not be LOW simultaneously.

3. Writes to the left port are internally ignored when BUSYL outputs are driving LOW regardless of actual logic level on the pin. Writes to the right port are internally ignored

when BUSYR outputs are driving LOW regardless of actual logic level on the pin.

Truth Tables

Truth Table II. Interrupt Flag(1,4)

NOTES:

1. A0L – A10L

≠ A0R – A10R.

2. If BUSY = L, data is not written.

3. If BUSY = L, data may not be valid, see tWDD and tDDD timing.

4. 'H' = VIH, 'L' = VIL, 'X' = DON’T CARE, 'Z' = HIGH IMPEDANCE

NOTES:

1. Assumes BUSYL = BUSYR = VIH

2. If BUSYL = VIL, then No Change.

3. If BUSYR = VIL, then No Change.

4. 'H' = HIGH, 'L' = LOW, 'X' = DON’T CARE

Left or Right Port(1)

Function

R/W

CE

OE

D0-7

X

H

X

Z

Port Disabled and in Power-Down Mode, ISB2 or ISB4

XH

X

Z

CER

= CEL = VIH, Power-Down Mode, ISB1 or ISB3

LL

X

DATAIN

Data on Port Written Into Memory(2)

HL

L

DATAOUT

Data in Memory Output on Por

t(3)

H

L

H

Z

High Impedance Outputs

2691 tbl 12

Left Port

Right Port

Function

R/WL

CEL

OEL

A10L-A0L

INTL

R/WR

CER

OER

A10R-A0R

INTR

L

L

X

7FF

XXX

X

X

L(2)

Set Right INTR Flag

X

X

XXX

X

L

L

7FF

H(3)

Reset Right INTR Flag

XXX

X

L(3)

LL

X

7FE

X

Set Left INTL Flag

XL

L

7FE

H(2)

XX

X

X

X

Reset Left INTL Flag

2691 tbl 13

Inputs

Outputs

Function

CEL

CER

A0L-A10L

A0R-A10R

BUSYL(1)

BUSYR(1)

X

X

NO MATCH

H

H

Normal

H

X

MATCH

H

H

Normal

X

H

MATCH

H

H

Normal

L

L

MATCH

(2)

(2)

Write Inhibit(3)

2691 tbl 14