IDT70825S/L

HIGH-SPEED 8K x 16 SEQUENTIAL ACCESS RANDOM ACCESS MEMORY

MILITARY AND COMMERCIAL TEMPERATURE RANGES

6.31

9

CASE 5: BUFFER FLOW MODES

Within the SARAM, the user can designate one of four

buffer flow modes for each buffer. Each buffer flow mode

defines a unique set of actions for the sequential port address

pointer and EOB flags. In BUFFER CHAINING mode, after the

address pointer reaches the end of the buffer, it sets the

corresponding EOB flag and continues from the start address

of the other buffer. In STOP mode, the address pointer stops

incrementing after it reaches the end of the buffer. In LINEAR

mode, the address pointer ignores the end of buffer address

and increments past it, but sets the EOB flag. MASK mode is

the same as LINEAR mode except EOB flags are not set.

15

MSB

LSB I/O BITS

3016 drw 10

H

H

12 ------------------------------------------------------------------------------------------------------------

Address Loaded into Buffer

0

14

13

H

reading and clearing the status of the EOB flags. Seven

different CMD cases are available depending on the condi-

RANDOM ACCESS PORT

CMD

CMD

CMD

CMD

Case #

A2-A0

R/

W

W

W

W

W

DESCRIPTIONS

1

000

0 (1)

2

001

0 (1)

3

010

0 (1)

4

011

0 (1)

5

100

0 (1)

Write (read) flow control register

6

101

0

7

101

1

Read only – flag status register

8

110/111

(X)

(Reserved)

NOTE:

1. R/

W input "0(1)" indicates a write(0) or read(1) occurring with the same address input.

3016 tbl 16

Register

Contents

Address Pointer

0

EOB Flags

Cleared to High state

Buffer Flow Mode

BUFFER CHAINING

Start Address Buffer #1

0

(1)

End Address Buffer #1

4095

(4K)

Start Address Buffer #2

4096

(4K+1)

End Address Buffer #2

8191

(8K)

Registered State

3016 tbl 15

Reset (

RST

RST

RST

RST

RST)

Setting

RST LOW resets the control state of the SARAM.

RST functions asynchronously of SCLK, (i.e. not registered).

The default states after a reset operation are as follows:

BUFFER COMMAND MODE (

CMD

CMD

CMD

CMD

CMD)

Buffer Command Mode (

CMD) allows the random access

and the end of buffer addresses and to set the flow control

mode of each buffer. The Buffer Command Mode also allows

NOTES:

2. A write into the buffer occurs when R/