SN54ACT7811

1024

× 18

CLOCKED FIRST-IN, FIRST-OUT MEMORY

SGAS001B – FEBRUARY 1995 – REVISED MARCH 1996

6

POST OFFICE BOX 655303

Terminal Functions (Continued)

TERMINAL†

I/O

DESCRIPTION

NAME

NO.

I/O

DESCRIPTION

WRTCLK

G8

I

Write clock. Data is written into memory on a low-to-high transition of WRTCLK if the IR output and

the WRTEN1 and WRTEN2 control inputs are high. WRTCLK is a free-running clock and functions

as the synchronizing clock for all data transfers into the FIFO. IR output is also driven synchronously

with respect to the WRTCLK signal.

WRTEN1,

WRTEN2

G9

F8

I

Write enables. WRTEN1 and WRTEN2 must be high before a rising edge on WRTCLK for a word

to be written into memory. The write enables do not affect the storage of the AF/AE offset value (X).

† Terminals listed are for the GB package.

12

3

4

1

2

12

3

4

Invalid

WRTCLK

WRTEN1

WRTEN2

D0 – D17

RDCLK

RDEN1

RDEN2

Q0 – Q17

OR

AF/AE

IR

Store the Value of D0 – D8 as X

Define the AF/AE Flag

Using the Value of X

HF

OE

X†

Don’t Care

Don’t Care

Don’t Care

Don’t Care

Don’t Care

Don’t Care

Don’t Care

Don’t Care

Don’t Care

Don’t Care

RESET

DAF

1

0

† X is the binary value of D0 – D8 only.

Figure 1. Reset Cycle: Define AF/AE Using the Value of X