70V25L25PFI Datasheet, PDF (6/25 Pages) Integrated Device Technology – True Dual-Ported memory cells which allow simultaneous reads of the same memory location

IDT70V35/34S/L (IDT70V25/24S/L)
High-Speed 3.3V 8/4K x 18 (8/4K x 16) Dual-Port Static RAM
Industrial and Commercial Temperature Ranges
Pin Names
Left Port
Right Port
Names
CEL
R/WL
CER
R/WR
Chip Enable
Read/Write Enable
OEL
OER
Output Enable
A0L - A12L⁽¹⁾
A0R - A12R⁽¹⁾
Address
I/O0L - I/O17L⁽²⁾
I/O0R - I/O17R⁽²⁾
Data Input/Output
SEML
SEMR
Semaphore Enable
UBL
LBL
INTL
BUSYL
UBR
LBR
INTR
BUSYR
M/S
Upper Byte Select⁽³⁾
Lower Byte Select⁽⁴⁾
Interrupt Flag
Busy Flag
Master or Slave Select
NOTES:
1. A12 is a NC for IDT70V34 and for IDT70V24.
2. I/O0x - I/O15x for IDT70V25/24.
3. Upper Byte Select controls pins 9-17 for IDT70V35/34 and controls pins 8-15
for IDT70V25/24.
4. Lower Byte Select controls pins 0-8 for IDT70V35/34 and controls pins 0-7
for IDT70V25/24.
VDD
Power (3.3V)
VSS
Ground (0V)
5624 tbl 01
Truth Table I: Non-Contention Read/Write Control
Inputs⁽¹⁾
Outputs
CE
R/W
OE
UB
LB
SEM
I/O9-17⁽³⁾
I/O0-8⁽²⁾
Mode
H
X
X
X
X
H
High-Z
High-Z Deselected: Power Down
X
X
X
H
H
H
High-Z
High-Z Both Bytes Deselected
L
L
X
L
H
H
DATAIN
High-Z Write to Upper Byte Only
L
L
X
H
L
H
High-Z
DATAIN Write to Lower Byte Only
L
L
X
L
L
H
DATAIN
DATAIN Write to Both Bytes
L
H
L
L
H
H
DATAOUT
High-Z Read Upper Byte Only
L
H
L
H
L
H
High-Z
DATAOUT Read Lower Byte Only
L
H
L
L
L
H
DATAOUT
DATAOUT Read Both Bytes
X
X
H
X
X
X
High-Z
High-Z Outputs Disabled
NOTES:
1. A0L-A12L ≠ A0R-A12R for IDT70V35/34 and A0L-A11L ≠ A0R-A11R for IDT70V25/24.
2. Outputs for IDT70V25/24 are I/O0x-I/O7x.
3. Outputs for IDT70V25/24 are I/O8x-I/O15x.
5624 tbl 02
Truth Table II: Semaphore Read/Write Control⁽¹⁾
Inputs
Outputs
CE
R/W
OE
UB
LB
SEM
I/O9-17⁽¹⁾
I/O0-8⁽¹⁾
Mode
H
H
L
X
X
L
DATAOUT
DATAOUT Read Data in Semaphore Flag
X
H
L
H
H
L
DATAOUT
DATAOUT Read Data in Semaphore Flag
H
↑
X
X
X
L
DATAIN
DATAIN Write I/O0 into Semaphore Flag
X
↑
X
H
H
L
DATAIN
DATAIN Write I/O0 into Semaphore Flag
L
X
X
L
X
L
____
____
Not Allowed
L
X
X
X
L
L
____
____
Not Allowed
NOTE:
5624 tbl 03
1. There are eight semaphore flags written to via I/O0 and read from all of the I/O's (I/O0-I/O17 for IDT70V35/34) and (I/O0-I/O15 for IDT70V25/24). These eight semaphores
are addressed by A0-A2.
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