ST70136

9/24

Figure 2 : Digital Data Interface

4.7 - Control Serial Interface

There is a 4-pin serial digital interface (CLKWD,

CTRLIN, CTRLOUT, R/W) that access one of the

8 x 12-bit registers that controls all the program-

mable features on the ST70136.

The registers are loaded with the asynchronous

type data burst delivered to CTRLIN pin. It is com-

posed of 16 bits from which the first bit (b15) is

used as start bit (‘0’), the three LSBs (b2:b0) being

used to identify the register to be loaded.

The twelve remaining bits (b14:b3) are the control

data. During a read operation, the CTRLOUT pin

figures out the register contents addressed by

CTRLIN pin.

CLKM

CLKWD

TX[0]/RX[0]

TX[1]/RX[1]

35.328MHz

8.832MHz

TX[2]/RX[2]

TX[3]/RX[3]

Sign

DATA..................................................................................LSB

a15

a0

TX DATA

Sign

Sign DATA.................................................................... 0

0 0

a15

RX DATA

a13

a9

a5

a12

a8

a4

a15

a11

a7

a3

a14

a10

a6

a2

a1

a0

a14

a13

a2

a14

a13

a0

a1

Figure 3 : Control Register Interface Write Cycle

CLKM

CLKWD

Data for write access [b14:b3]

[b2:b0]

CTRLIN

b15

CTRLOUT

R/NW