SN74ALS232B

16

× 4 ASYNCHRONOUS FIRST-IN, FIRST-OUT MEMORY

SCAS251B – FEBRUARY 1989 – REVISED APRIL 1998

2

POST OFFICE BOX 655303

CT = 0

9

EN4

1

OE

2D

4

D0

Q0

13

5

D1

Q1

12

6

D2

Q2

11

7

D3

Q3

10

15

UNCK

14

(CT = 0) G3

2

(CT = 16) G1

3

LDCK

FIFO 16

× 4

CTR

RST

FULL

EMPTY

3–

1(+/C2)

4

† This symbol is in accordance with ANSI/IEEE Standard 91-1984 and IEC Publication 617-12. The symbol is functionally accurate but does

not show the details of implementation; for these, see the logic diagram. The symbol represents the memory as if it were controlled by a single

counter whose content is the number of words stored at the time. Output data is invalid when the counter content (CT) is 0.

Pin numbers shown are for the DW and N packages.