MA780 – 8-BIT TO 12-BIT LOW-POWER ANGLE SENSOR

MA780 Rev. 1.2

MonolithicPower.com

13

8/30/2021

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Figure 16 shows a complete read register

transmission overview. Figure 17 shows a

complete read register example.

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

Angle

0

1

0

4

3

2

1

0

7

6

5

4

3

2

1

0

0x00

/CS

SCLK

MISO

MOSI

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

7

6

5

4

3

2

1

0

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0x0000

Read Command

Register Address

7

6

5

4

3

2

1

0

Register Value

Angle

tIDLE_READ_REG

Figure 16: Two 16-Bit Frames Read Register Operation

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

Angle

0

1

0

4

3

2

1

0

7

6

5

4

3

2

1

0

0x00

/CS

SCLK

MISO

MOSI

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

7

6

5

4

3

2

1

0

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0x0000

Read Command

26 (0x1A)

7

6

5

4

3

2

1

0

Register 26 Value

Angle

tIDLE_READ_REG

Figure 17: Read the Status Byte in Register 26

SPI Write Register

A write register operation is made of two 16-bit

frames. The first frame sends a write request,

which contains the 3-bit write command (100)

followed by the 5-bit register address and the 8-

bit value (MSB first). The second frame returns

the newly written register value (acknowledge)

with an 8-bit angle value. In ASC mode, if the

write command is sent when the sensor is in a

transition from an active state to an idle state, the

write command might fail. Therefore, it is

recommended to verify that the write command

was

successful

by

reading

the

acknowledgement.

The first 16-bit SPI frame (write request) is as

follows:

MSB

LSB

MISO

Angle(15:0)

Command

Reg. Address

Reg. Value

MOSI

1

0

0

A4 A3 A2 A1 A0 V7 V6 V5 V4 V3 V2 V1 V0

The second 16-bit SPI frame (response) is as

follows:

Reg. Value

MISO

Angle(15:8)

V7 V6 V5 V4 V3 V2 V1 V0

MSB

LSB

MOSI

0

The readback register content can be used to

verify the register configuration. Figure 18 shows

a complete transmission overview.

For example, to set the value of the output

rotation direction (RD) to counterclockwise (RD

bit = logic 1), write register 9 by sending the

following first frame:

Reg. Value

MISO

Angle(15:8)

1 0 0 0 0 0 0 0

MSB

LSB

MOSI

0

Figure 19 shows a complete example.