HAL855 datasheet(21/102 Pages) MICRONAS

21 / 102 page

APPLICATION NOTE

HAL8xy, HAL100x

Programmer Board

Micronas

Sept. 19, 2013; APN000046_03EN

4.3.

Programming of the Sensor

4.3.1.

Definition of Programming Pulses

The sensor is addressed by modulating a serial telegram on the supply voltage. The

sensor answers with a serial telegram on the output pin.

The bits in the serial telegram have a different bit time for the VDD-line and the output.

The bit time for the VDD-line is defined through the length of the Sync bit at the begin-

ning of each telegram. The bit time for the output is defined through the Acknowledge

bit.

A logical “0” is coded as no voltage change within the bit time. A logical “1” is coded as

a voltage change between 50% and 80% of the bit time. After each bit, a voltage

change occurs.

4.3.2.

Definition of the Telegram

Each telegram starts with the Sync bit (logical 0), 3 bits for the Command (COM), the

Command Parity bit (CP), 4 bits for the Address (ADR), and the Address Parity bit (AP).

There are 4 kinds of telegrams:

Write a register

After the AP bit, follow 14 Data bits (DAT) and the Data Parity bit (DP). If the telegram is

valid and the command has been processed, the sensor answers with an Acknowledge

bit (logical 0) on the output (see Fig. 4–2).

Read a register

After evaluating this command, the sensor answers with the Acknowledge bit, 14 Data

bits, and the Data Parity bit on the output (see Fig. 4–3).

Programming the

EEPROM cells

After evaluating this command, the sensor answers with the Acknowledge bit. After the

delay time tw, the supply voltage rises up to the programming voltage (see Fig. 4–4).

Activate a sensor

If more than one sensor is connected to the supply line, selection can be done by first

deactivating all sensors. The output of all sensors will be pulled to ground by the inter-

nal 10 k

 resistors. With an activate pulse on the appropriate output pin, an individual

sensor can be selected. All following commands will only be accepted from the acti-

vated sensor (see Fig. 4–5).

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