4

T6818/T6828

4530C–BCD–11/03

Functional Description

Serial Interface

Data transfer starts with the falling edge of the CS signal. Data must appear at DI syn-

chronized to CLK and are accepted on the falling edge of the CLK signal. LSB (bit 0,

SRR) has to be transferred first. Execution of new input data is enabled on the rising

edge of the CS signal. When CS is high, pin DO is in tristate condition. This output is

enabled on the falling edge of CS. Output data will change their state with the rising

edge of CLK and stay stable until the next rising edge of CLK appears. LSB (bit 0, TP) is

transferred first.

Figure 3. Data Transfer

Table 1. Input Data Protocol

Bit

Input Register

Function

0SRR

Status register reset (high = reset; the bits PSF, OPL and SCD in

the output data register are set to low)

1

LS1

Controls output LS1 (high = switch output LS1 on)

2

HS1

Controls output HS1 (high = switch output HS1 on)

3

LS2

See LS1

4

HS2

See HS1

5

LS3

See LS1

6

HS3

See HS1

7

n. u.

Not used

8

n. u.

Not used

9

n. u.

Not used

10

n. u.

Not used

11

n. u.

Not used

12

n. u.

Not used

13

OCS

Overcurrent shutdown (high = overcurrent shutdown is active)

14

n. u.

Not used

15

n. u.

Not used

SRR

LS1

HS1

LS2

HS2

LS3

HS3

n. u.

n. u.

n. u.

n. u.

n. u.

n. u.

OCS

n. u.

n. u.

CS

DI

CLK

DO

TP

S1L

S1H

S2L

S2H

S3L

S3H

n. u.

n. u.

n. u.

n. u.

n. u.

n. u.

SCD

OPL

PSF

0

1234

567

89

10

11

12

13

14

15