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AS5140H

Data Sheet - D e t a i l e d D e s c r i p t i o n

The absolute angular position is sampled at a rate of 10kHz (0.1ms). This allows reading of all 1024 positions per 360 degrees within 0.1

seconds = 9.76Hz (~10Hz) without skipping any position. Multiplying 10Hz by 60, results the corresponding maximum rotational speed of 600

rpm. Readout of every second angular position allows for rotational speeds of up to 1200 rpm.

Consequently, increasing the rotational speed reduces the number of absolute angular positions per revolution (see Table 21). Regardless of the

rotational speed or the number of positions to be read out, the absolute angular value is always given at the highest resolution of 10 bit.

The incremental outputs are not affected by rotational speed restrictions due to the implemented interpolator. The incremental output signals

may be used for high-speed applications with rotational speeds of up to 10.000 rpm without missing pulses.

7.1.2 Daisy Chain Mode

The Daisy Chain mode allows connection of several AS5140H’s in series, while still keeping just one digital input for data transfer (see “Data IN”

in Figure 6 below). This mode is accomplished by connecting the data output (DO; pin 9) to the data input (Prog; pin 8) of the subsequent device.

The serial data of all connected devices is read from the DO pin of the first device in the chain. The Prog pin of the last device in the chain should

be connected to VSS. The length of the serial bit stream increases with every connected device. It is,

n * (16+1) bits

(EQ 1)

For example, 34 bit for two devices, 51 bit for three devices, etc.

The last data bit of the first device (Parity) is followed by a logic low bit and the first data bit of the second device (D9), etc. (see Figure 7).

Figure 6. Daisy Chain Hardware Configuration

Figure 7. Daisy Chain Mode Data Transfer

CSn

CSn

CSn

CSn

CLK

CLK

CLK

CLK

Data IN

AS5140H

1

AS5140H

2

AS5140H

last Device

µC

DO

DO

DO

Prog

Prog

Prog

CSn

CLK

DO

Angular Position Data

Status Bits

1

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0

OCF COF LIN

Mag

INC

Mag

DEC

Even

PAR

8

16

D

D9

1

2

3

D8

D7

Angular Position Data

1

2