18

IDT70V06S/L

High-Speed 3.3V 16K x 8 Dual-Port Static RAM

Industrial and Commercial Temperature Ranges

Truth Table IV — Address BUSY

Arbitration

NOTES:

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

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

NOTES:

1. This table denotes a sequence of events for only one of the eight semaphores on the IDT70V06.

Functional Description

The IDT70V06 provides two ports with separate control, address

and I/O pins that permit independent access for reads or writes to any

location in memory. The IDT70V06 has an automatic power down

feature controlled by CE. TheCEcontrolson-chippowerdowncircuitry

that permits the respective port to go into a standby mode when not

memory array is permitted.

Interrupts

If the user chooses the interrupt function, a memory location (mail

box or message center) is assigned to each port. The left port interrupt

(HEX). Theleftportclearstheinterruptbyreadingaddresslocation3FFE.

rightportmustreadthememorylocation3FFF.Themessage(8bits)at

3FFEor3FFFisuser-defined.Iftheinterruptfunctionisnotused,address

locations 3FFE and 3FFF are not used as mail boxes, but as part of the

random access memory. Refer to Truth Table III for the interrupt

operation.

Busy Logic

Busy Logic provides a hardware indication that both ports of the

SRAM have accessed the same location at the same time. It also

Inputs

Outputs

Function

X

X

NO MATCH

H

H

Normal

H

X

MATCH

H

H

Normal

X

H

MATCH

H

H

Normal

L

L

MATCH

(2)

(2)

2942 tbl 16

Functions

Status

No Action

1

1

Semaphore free

Left Port Writes "0" to Semaphore

0

1

Left port has semaphore token

Right Port Writes "0" to Semaphore

0

1

No change. Right side has no write access to semaphore

Left Port Writes "1" to Semaphore

1

0

Right port obtains semaphore token

Left Port Writes "0" to Semaphore

1

0

No change. Left port has no write access to semaphore

Right Port Writes "1" to Semaphore

0

1

Left port obtains semaphore token

Left Port Writes "1" to Semaphore

1

1

Semaphore free

Right Port Writes "0" to Semaphore

1

0

Right port has semaphore token

Right Port Writes "1" to Semaphore

1

1

Semaphore free

Left Port Writes "0" to Semaphore

0

1

Left port has semaphore token

Left Port Writes "1" to Semaphore

1

1

Semaphore free

2942 tbl 17