AS5040 datasheet(5/28 Pages) AMSCO

5 / 28 page

AS5040 10-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER

Revision 1.6, 03-Oct-06

www.austriamicrosystems.com

Page 5 of 28

The absolute angular output is always set to a resolution

of 10 bit. Placing the magnet above the chip, angular

values increase in clockwise direction by default.

Data D9:D0 is valid, when the status bits have the

following configurations:

OCF

COF

LIN

Mag

INCn

Mag

DECn

Parity

even

checksum of

bits 1:15

Table 4: Status bit outputs

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 1200rpm.

Consequently, increasing the rotational speed reduces

the number of absolute angular positions per revolution

(see Table 7). 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.

4.2

Daisy Chain Mode

The Daisy Chain mode allows connection of several

AS5040’s in series, while still keeping just one digital

input for data transfer (see “Data IN” in Figure 5 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:

e.g. 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 6).

4.2.1

Programming Daisy Chained Devices

In Daisy Chain mode, the Prog pin is connected directly

to the DO pin of the subsequent device in the chain (see

Figure 5). During programming (see section 9), a

programming voltage of 7.5V must be applied to pin

Prog. This voltage level exceeds the limits for pin DO, so

one of the following precautions must be made during

programming:

•

open

the

connection

DO Prog

during

programming or

•

add a Schottky diode between DO and Prog

(Anode = DO, Cathode = Prog)

Due to the parallel connection of CLK and CSn, all

connected devices may be programmed simultaneously.

AS5040

1st Device

Prog

CLK

CSn

CLK

µC

Prog

CLK

CSn

Prog

CLK

CSn

Data IN

CSn

AS5040

2nd Device

AS5040

last Device

Figure 5: Daisy Chain hardware configuration

AS5040 데이터시트(PDF) 5 Page - ams AG

AS5040 데이터시트(HTML) 5 Page - ams AG

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

데이터시트 다운로드

링크 URL