HAL855UT-K datasheet(11/42 Pages) MICRONAS

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DATA SHEET

HAL855

Micronas

Nov. 26, 2008; DSH000149_003EN

Output Bittime

The OUTPUT BITTIME register defines the bit time of

the Biphase-M output signal. OUTPUT BITTIME is

“sub”-register of the SPECIAL CUSTOMER register.

Note: Setting the Biphase-M bit time to 40

μs simulta-

neously switches the programming telegram to

the same bit time. Hence after writing the

OUTPUT BITTIME register the timing of the pro-

gramming device has to be set accordingly.

TC and TCSQ

The temperature dependence of the magnetic sensitiv-

ity can be adapted to different magnetic materials in

order to compensate for the change of the magnetic

strength with temperature. The adaption is done by

programming the TC (Linear Temperature Coefficient)

and the TCSQ registers (Quadratic Temperature Coef-

ficient). Thereby, the slope and the curvature of the

temperature dependence of the magnetic sensitivity

can be matched to the magnet and the sensor assem-

bly. As a result, the output signal characteristic can be

fixed over the full temperature range. The sensor can

compensate for linear temperature coefficients ranging

from about

−2100 ppm/K up to 600 ppm/K and qua-

dratic coefficients from about

−5ppm/K2 to 5 ppm/K2.

Please refer to Section 4.4. on page 28 for the recom-

mended settings for different linear temperature coeffi-

cients.

Slope

The SLOPE register contains the parameter for the

multiplier in the DSP. The Slope is programmable

between

−4 and 4. The register can be changed in

steps of 0.00049. Slope = 1 corresponds to an

increase of the output signal by 100% if the digital

value at the A/D-converter output increases by 2048.

For all calculations, the digital value after the digital

signal processing is used. This digital information is

readable from the DIGITAL OUTPUT register.

Shift

The SHIFT register contains the parameter for the

adder in the DSP. Shift is the output signal without

external magnetic field (B = 0 mT) and programmable

from

−100% up to 100%. For calibration in the system

environment, a 2-point adjustment procedure is rec-

ommended. The suitable Slope and Shift values for

each sensor can be calculated individually by this pro-

cedure.

Part Number

In case of Biphase-M output, a part number can be

defined. This part number will be sent during power-on

of the sensor if the PARTNUMBER ENABLE bit is set.

Afterwards, the sensor will send the digital value corre-

sponding to the applied magnetic field.

– The PARTNUMBER ENABLE bit is part of the

SPECIAL CUSTOMER register.

– The OUTPUT PERIOD register defines the time

interval for which the part number is sent.

Output Characteristic

The OUTPUT CHARACTERISTIC register defines the

shape of the sensor output signal. It consists of

32 setpoints. Each setpoint can be set to values

between 0 and 511 LSB. The output characteristic has

to be monotonic increasing (Setpoint0

≤ Setpoint1

≤ SetpointN).

LOCKR

By setting this 1-bit register, all registers will be locked,

and the sensor will no longer respond to any supply

voltage modulation. This bit is active after the first

power-off and power-on sequence after setting the

LOCK bit.

Warning: This register cannot be reset!

Table 2–5: OUTPUT BITTIME register definition

Biphase-M Output Bit Time

Bit Setting

μs0

84 µs

168 µs

320 µs

700 µs

1.6 ms

3.2 ms

6.4 ms

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