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sames

sames

SA9903B

http://www.sames.co.za

OUTPUT SIGNALS

SERIAL DATA OUT (DO)

The DO pin is the serial data output pin for the SA9903B. The

Serial Clock (SCK) determines the data output rate. Data is

only transferred during on active chip select (CS). This output

is tri-state when CS is low.

MAINS VOLTAGE SENSE ZERO CROSSOVER

(FMO)

The FMO output generates a signal, which follows the mains

voltage zero crossings, see figure 4. The micro controller may

use the FMO to extract mains timing.

ELECTROSTATIC DISCHARGE (ESD) PROTECTION

The SA9903B Integrated Circuit's inputs/outputs are protected

against ESD.

POWER CONSUMPTION

The power consumption rating of the SA9903B integrated

circuit is less than 25mW.

Figure 4: Mains voltage zero corssover pin FMO

ID

1

2

3

4

Register

Active

Reactive

Voltage

Frequency

1

1

1

1

1

1

1

1

0

0

0

0

A5

X

X

X

X

A4

X

X

X

X

A3

0

0

0

0

A2

0

0

0

0

A1

0

0

1

1

A0

0

1

0

1

Header

bits

SPI - INTERFACE

DESCRIPTION

A serial peripheral interface bus (SPI) is a synchronous bus

used for data transfers between a micro controller and the

SA9903B. The pins DO (Serial Data Out), DI (Serial Data In),

CS (Chip Select), and SCK (Serial Clock) are used in the bus

implementation. The SA9903B is the slave device with the

micro controller the bus master. The CS input initiates and

terminates data transfers. A SCK signal (generated by the

micro controller) strobes data between the micro-controller

and the SCK pin of the SA9903B device. The DI and DO pins

are the serial data input and output pins for the SA9903B,

respectively.

REGISTER ACCESS

The SA9903B contains four 24 bit registers. The content

represents active energy, reactive energy, mains voltage and

mains frequency. The register addresses are shown in the

following table:

Dr-01498

Voltage

+5V (V )

DD

0V (V )

SS

FM0