AS5045 datasheet(23/47 Pages) AMSCO

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[v2-01] 2017-Jul-13

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AS5045 − Detailed Description

OTP Register Contents

CCW: Counter Clockwise Bit

ccw=0 – angular value increases in clockwise direction

ccw=1 – angular value increases in counter clockwise direction

Z [11:0]: Programmable Zero Position

PWM dis: Disable PWM output

MagCompEn: When set, activates LIN alarm both when

magnetic field is too high and too low (see Figure 16)

PWMhalfEn: When set, PWM frequency is 122Hz or 2μs / step

(when PWMhalfEN = 0, PWM frequency is 244Hz, 1μs / step)

Zero Position Programming

Zero position programming is an OTP option that simplifies

assembly of a system, as the magnet does not need to be

manually adjusted to the mechanical zero position. Once the

assembly is completed, the mechanical and electrical zero

positions can be matched by software. Any position within a

full turn can be defined as the permanent new zero position.

For zero position programming, the magnet is turned to the

mechanical zero position (e.g. the “off ”-position of a rotary

switch) and the actual angular value is read.

This value is written into the OTP register bits Z11:Z0

(see Figure 23) and programmed (see Figure 24).

The zero position value may also be modified before

programming, e.g. to program an electrical zero position that

is 180° (half turn) from the mechanical zero position, just add

2048 to the value read at the mechanical zero position and

program the new value into the OTP register.

Repeated OTP Programming

Although a single AS5045 OTP register bit can be programmed

only once (from 0 to 1), it is possible to program other,

unprogrammed bits in subsequent programming cycles.

However, a bit that has already been programmed should not

be programmed twice. Therefore it is recommended that bits

that are already programmed are set to “0” during a

programming cycle.

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