6.42
IDT71321SA/LA and IDT71421SA/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 BUSY
L 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 BUSY
X 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 t
APS 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 BUSY
L outputs are driving LOW regardless of actual logic level on the pin. Writes to the right port are internally ignored
when BUSY
R outputs are driving LOW regardless of actual logic level on the pin.
Truth Tables
Truth Table II. Interrupt Flag
(1,4)
NOTES:
1. A
0L – A10L ≠ A0R – A10R.
2. If BUSY = L, data is not written.
3. If BUSY = L, data may not be valid, see t
WDD and tDDD timing.
4. 'H' = V
IH, 'L' = VIL, 'X' = DON’T CARE, 'Z' = HIGH IMPEDANCE
NOTES:
1. Assumes BUSY
L = BUSYR = VIH
2. If BUSYL = VIL, then No Change.
3. If BUSY
R = VIL, then No Change.
4. 'H' = HIGH, 'L' = LOW, 'X' = DON’T CARE
Left or Right Port
(1)
FunctionR/W
CE OE
D
0-7
X H X Z Port Disabled and in Power-Down Mode, ISB
2
or ISB
4
XHX Z
CE
R
= CE
L
= V
IH
, Power-Down Mode, ISB
1
or ISB
3
LLXDATA
IN
Data on Port Written Into Memory
(2 )
HLLDATA
OUT
Data in Memory Output on Por
t
(3 )
H L H Z High Impedance Outputs
2691 tbl 12
Left Port Right Port
FunctionR/W
L
CE
L
OE
L
A
10L
-A
0L
INT
L
R/W
R
CE
R
OE
R
A
10R
-A
0R
INT
R
LLX7FFXXXX X L
(2 )
Set Right INT
R
Flag
XXXXXXLL7FF H
(3)
Reset Right INT
R
Flag
XXX X L
(3 )
L L X 7FE X Set Left INT
L
Flag
XLL7FE H
(2 )
X X X X X Reset Left INT
L
Flag
2691 tbl 13
Inputs Outputs
Function
CE
L
CE
R
A
0L
-A
10L
A
0R
-A
10R
BUSY
L
(1 )
BUSY
R
(1)
XXNO MATCH H H Normal
HX MATCH H H Normal
XH MATCH H H Normal
L L MATCH (2) (2) Write Inhibit
(3 )
2691 tbl 14
