MAQ473

– 9-BIT TO 14-BIT, AUTOMOTIVE ANGLE SENSOR W/ ABZ & PWM OUTPUTS

MAQ473 Rev. 1.0

MonolithicPower.com

12

5/12/2021

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© 2021 MPS. All Rights Reserved.

SPI Communication

The

sensor

supports

three

types

of

SPI

operation:

 Read angle

 Read configuration register

 Write configuration register

Each operation has a specific frame structure,

described below.

SPI Read Angle

Every 1µs, new data is transferred into the

output buffer. The master device triggers the

reading by pulling CS low.

When a trigger event is detected, the data

remains in the output buffer until the CS signal

is de-asserted (see Table 4).

Table 4: Sensor Data Timing

Event

Action

CS falling edge

Start reading and freeze the

output buffer

CS rising edge

Release the output buffer

Figure 9 shows a diagram of a full SPI angle

reading. Figure 10 shows a partial SPI angle

reading. A full angle reading requires 16 clock

pulses. The sensor MISO line returns:

MSB

LSB

MISO

Angle[15:0]

MOSI

0

The MagAlpha family has sensors with different

features and levels of resolution. See the data

output

length

section

in

the

General

Characteristics section on page 5 for the

number of useful bits delivered at the serial

output. If the data length is less than 16, the

rest of the bits sent are 0s. For example, a data

output length of 12 bits means that the serial

output delivers a 12-bit angle value with 4 bits

of 0s padded at the end (the MISO state

remains 0). If the master sends 16 clock counts,

the MAQ473 replies with:

MSB

LSB

MISO

Angle[15:4]

0 0 0 0

MOSI

0

Angle reading can be therefore optimized

without any loss of information by reducing the

number of clock counts. In the case of a 12-bit

data output length, only 12 clock counts are

required to get the full sensor resolution.

MSB

LSB

MISO

Angle[15:4]

MOSI

0

If less resolution is needed, the angle can be

read by sending even fewer clock counts (since

the MSB is first).

In case of fast reading, the MAQ473 continues

sending the same data until the data is

refreshed. See the refresh rate section in the

General Characteristics section on page 5.

Figure 9: Full 16-Bit SPI Angle Reading Diagram

Figure 10: Partial 8-Bit SPI Angle Reading

Diagram