MA800 – 8-BIT, DIGITAL ANGLE SENSOR

MA800 Rev. 1.02

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15

6/15/2018

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Figure 14: Example Write Output Rotation Direction (RD) to Counterclockwise (High) on Register 9, Bit 7

SSI

SSI is a 2-wire synchronous serial interface for

data reading only. The sensor operates as a

slave to the external SSI master and supports

angle reading only. It is not possible to read or

write registers using SSI.

SSI Communication

Unlike SPI, the sensor SSI supports angle

reading operation only. It is not possible to read

or write registers using SSI. The SSI timing

communication is shown in Figure 15 and Table

5.

Figure 15: SSI Timing

Table 5: SSI Timing

Parameter

Description

Min

Max

Unit

tssd

15

ns

tssck

SSCK period

0.04

16

µs

tssckL

Low level of SSCK signal

0.02

8

µs

tssckH

High level of SSCK signal

0.02

8

µs

tm

Transfer timeout (monoflop time)

25

µs

tp

Dead time: SSCK high time for next data reading

40

µs

SSI Read Angle

The bit order of the transmitted data is MSB first

and

LSB

last.

Every

1µs,

new

data

is

transferred into the output buffer. The master

device triggers the reading by pulling SSCK

down. Just like with an SPI reading, a full

reading requires 16 clock counts, but if the data

length is less than 16, the 16-bit output word is

completed by zeros. Therefore, reading can

also be performed with fewer than 16 clock

counts (see Figure 16). When a trigger event is

detected, the data remains in the output buffer

until the clock rising edge for the LSB bit 0 and

the transfer time out time has passed. See

Table 6 for sensor data timing.