ASAHI KASEI

[AK93C45A/55A/65A/75A]

DAM01E-02

2002/06

- 6 -

READ

The read instruction is the only instruction which outputs serial data on the DO pin.

Following the Start bit, first Op code and address are decoded, then the data from the selected

memory location is available at the DO pin. A dummy bit (logical "0") precedes the 16-bit data from

the selected memory location. The output data changes are synchronized with the rising edges of

the serial clock (SK).

The data in the next address can be read sequentially by continuing to provide clock. The address

automatically cycles to the next higher address after the 16bit data shifted out.

When the highest address is reached, the address counter rolls over to address $00 or $000 allowing

the read cycle to be continued indefinitely.

READ (AK93C45A)

*Address bit A7 becomes a "don't care" for AK93C55A.

READ (AK93C55A/65A)

READ (AK93C75A)

address[A5–A0]+1

AK93C45A output a logic "1" (Ready status),

if previous instruction is WRITE.

Hi-Z

Hi-Z

Dummy

Bit

address[A5–A0]

0

CS

SK

DI

DO

Start bit

Op code

D0

1

2345

8

9

10

11

D14

D15

A0

A1

A4

A5

0

1

1

0

25

26

40

41

D15

D1

D0

0

address[A6/A7–A0]+1

AK93C55A/65A output a logic "1" (Ready status),

if previous instruction is WRITE.

Hi-Z

Hi-Z

Dummy

Bit

address[A6/A7–A0]

0

CS

SK

DI

DO

Start bit

Op code

D0

1

2345

12

13

D14

D15

A0

A1

A6

0

1

1

0

27

28

42

43

D15

D1

D0

0

A7

X /

X: Don't care

10

11

14

15

address[A8–A0]+1

AK93C75A output a logic "1" (Ready status),

if previous instruction is WRITE.

Hi-Z

Hi-Z

Dummy

Bit

address[A8–A0]

0

CS

SK

DI

DO

Start bit

Op code

D0

1

2345

12

13

D14

D15

A0

A1

A8

0

1

1

0

29

30

44

45

D15

D1

D0

0

X

X: Don't care