HAR2425 datasheet(13/33 Pages) MICRONAS

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DATA SHEET

HAR 24xy

Micronas

July 14, 2015; DSH000170_001EN

CUST_ID1 and CUST_ID2

The two registers CUST_ID1 and CUST_ID2 can be

used to store customer information. Both registers

have a length of 16 bit each.

Barrel Shifter (Magnetic Ranges)

The signal path of HAR 24xy contains a Barrel Shifter

to emulate magnetic ranges. The customer can select

between different magnetic ranges by changing the

Barrel Shifter setting. After decimation filter the signal

path has a word length of 22 bit. The Barrel Shifter

selects 16 bit out of the available 22 bit.

The Barrel Shifter bits are part of the CUSTOMER

SETUP register (bits 14...12). The CUSTOMER

SETUP register is described on the following pages.

Note: In case that the external field exceeds the mag-

netic field range the CFX register will be

clamped either to

32768 or 32767 depending

on the sign of the magnetic field.

Magnetic Sensitivity TCCG

The TCCG (Sensitivity) registers (TCCG0...TCCG2)

contain the customer setting temperature dependant

gain factor. The multiplication factor is a second order

polynomial of the temperature.

All three polynomial coefficients have a bit length of 16

bit and they are two’s-complement coded. Therefore

the register values can vary between

32768...32767.

In case that the target polynomial is based on normal-

ized values, then each coefficient can vary between

4 ... +4. To store each coefficient into the EEPROM it

is necessary to multiply the normalized coefficients

with 32768.

Example:

– Tccg0 = 0.5102 => TCCG0 = 16719

– Tccg1 =

0.0163 => TCCG1 = 536

– Tccg2 = 0.0144 => TCCG2 = 471

In case that the polynomial was calculated based on

not normalized values of TEMP_ADJ and MIC_COMP,

then it is not necessary to multiply the polynomial coef-

ficients with a factor of 32768.

Magnetic Sensitivity TCCO

The TCCO (Offset) registers (TCCO0 and TCCO1)

contain the parameters for temperature dependant off-

set correction. The offset value is a first order polyno-

mial of the temperature.

Both polynomial coefficients have a bit length of 16 bit

and they are two’s-complement coded. Therefore the

32768...32767.

In case that the target polynomial is based on normal-

ized values, then each coefficient can vary between

4 ... +4. To store each coefficient into the EEPROM it

is necessary to multiply the normalized coefficients

with 32768.

In case that the polynomial was calculated based on

not normalized values of TEMP_ADJ and MIC_COMP,

then it is not necessary to multiply the polynomial coef-

ficients.

In addition HAR 24xy features a linearization function

based on 16 setpoints. The setpoint linearization in

general allows to linearize a given output characteristic

by applying the inverse compensation curve.

Each of the 16 setpoints (SETPT) registers have a

length of 16 bit. The setpoints have to be computed

and stored in a differential way. This means that if all

setpoints are set to 0, then the linearization is set to

neutral and a linear curve is used.

Sensitivity and Offset Scaling before Setpoint

Linearization SCALE_GAIN/SCALE_OFFSET

The setpoint linearization uses the full 16 bit number

range 0...32767 (only positive values possible). So the

signal path should be properly scaled for optimal

usage of all 16 setpoints.

For optimum usage of the number range an additional

scaling stage is added in front of the set point algo-

rithm. The setpoint algorithm allows positive input

numbers only.

The input scaling for the linearization stage is done

with

the

EEPROM

registers

SCALE_GAIN

and

SCALE_OFFSET. The register content is calculated

based on the calibration angles. Both registers have a

bit length of 16 bit and are two’s-complemented coded.

Table 3–2: Relation between Barrel Shifter setting and

emulated magnetic range

BARREL SHIFTER

Used bits

Typ. magnetic range

22...7

not used

21...6

200 mT

20...5

100 mT

19...4

 50 mT

18...3

 25 mT

17...2

12 mT

16...1

 6mT

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