SA9110A

sames

13/18

8.

Electrostatic Discharge (ESD) Protection

The SA9110A integrated circuits inputs/outputs are protected against ESD.

9.

Power Consumption

The power consumption rating of the SA9110A integrated circuit is less than 40mW

with a 5V supply.

6.

Optical Interface

The SA9110A device contains an interface for automatic meter reading, according

to the IEC1107 Mode D standard. The IEC1107 Mode D is a single baud rate of

2400. For the optical interface protocol, the 4-bit words are converted to 8-bit words

(ASCII-format).

After initiation of a serial transmission by pulling PB (pin 66) low, the data format

transmitted on SDO, is given below:

Code

Description

/

Start transmission

XXX

ID

3

Baud rate identification

YYYYYYYY

ID

<cr><lf><cr><lf>

Data header

0(nnnnnnnn)

1(nnnnnnnn)

Data of Reg. 2

2(nnnnnnnn)

Data of Reg. 3

3(nnnnnnnn)

Data of Reg. 4

4(nnnnnnnn)

Data of Reg. 'Total' = Sum of registers 1 to 4

!<cr><lf><cr><lf>

End transmission

7.

Power Failure/Battery Backup

A battery backup facility is available on VBA. This feature is provided to ensure

retention of the information stored in the registers, in case of power breaks.

The VSS supply to the analog circuitry and digital circuitry has been separated. In

the event of a power failure, the supply to the analog circuitry falls to 0V. The digital

circuitry is switched to a power down mode, to minimise the supply current from an

external battery backup. During this procedure, the following events take place:

• All inputs are disabled

• All outputs are placed in high impedance mode

• The oscillator is inhibited

• The LCD driver is disabled

• The contents of the RAM is retained by means of an external power source.