CAT24C208

10

Doc. No. 1044, Rev. F

© 2006 by Catalyst Semiconductor, Inc.

Characteristics subject to change without notice

CONFIGURATION REGISTER

Function Description:

NB:

Number of memory banks in DDC port memory map. 0 = 2 Banks, 1 = 1 Bank

AB0:

Active Bank Control Bit 0 (See Figure 19)

AB1:

Active Bank Control Bit 1 (See Figure 19)

WE DDC:

Write Enable 0 = Write Disabled, 1= Write Enabled

Note: WE affects only write operations from the DDC port, not the display port. The display port always has write access.

Figure 19. Configuration Register Truth Table

ARBITRATION

The device performs a simplistic arbitration between the

DDC and DSP ports. While the arbitration scheme

described is not foolproof, it does prevent most errors.

Arbitration logic within the device monitors activity on

DDC_SCL and DSP_SCL. When both I2C ports are idle,

DDC_SCL and DSP_SCL are both high and the

arbitration logic is inactive. When a START condition is

detected on either port, the opposite port SCL line is

pulled low, holding off activity on that port. When the

initiating SCL line has remained high for one full second,

the arbitration logic assumes that the initiating devices is

finished and releases the other SCL line. If the non-

initiating device has been waiting for access, it can now

read or write the device.

1

B

A0

B

AB

N

D

I

D

E

n

i

P

t

c

e

l

e

S

k

n

a

B

e

v

i

t

c

A

0X

0

0

k

n

a

B

r

e

w

o

L

0X

0

1

k

n

a

B

r

e

p

p

U

10

0

X

k

n

a

B

r

e

w

o

L

11

0

X

k

n

a

B

r

e

p

p

U

XX

1

X

k

n

a

B

)

y

l

n

o

(

r

e

w

o

L

The configuration register is a non-volatile register and

is available from either DSP or DDC port at address 62h/

63h for write and read resp.

Figure 20. Read Configuration Register

Figure 21. Write Configuration Register

T

R

A

T

S0

1

0

0

0

1

1

0K

C

AS

S

E

R

D

D

A

Y

M

M

U

DK

C

AB

N

0

B

A

1

B

A

E

W

X

X

X

XK

C

AP

O

T

S

T

R

A

T

S1

1

0

0

0

1

1

0K

C

AA

T

A

DK

C

A

O

NP

O

T

S

n

o

i

t

c

n

u

F

r

e

t

s

i

g

e

R

B

S

MB

S

L

76

5

4

3

2

1

0

r

e

t

s

i

g

e

R

n

o

i

t

a

r

u

g

i

f

n

o

C

XX

X

X

E

W1

B

A0

B

AB

N