AS5040-ASSM View Datasheet(PDF) - austriamicrosystems AG

Part Name

Description

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AS5040-ASSM

10-Bit 360º Programmable Magnetic Rotary Encoder

austriamicrosystems AG 

AS5040 − 10-Bit Absolute Angular Position Output

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 24 below). This mode is

accomplished by connecting the data output (DO; pin 9) to the

data input (Prog; pin 8) of the subsequent device. An RC filter

must be implemented between each PROG pin of device n and

DO pin of device n+1, to prevent the encoders to enter the

alignment mode, in case of ESD discharge, long cables, or not

conform signal levels or shape. Using the values R=100R and

C=1nF allow a max. CLK frequency of 1MHz on the whole chain.

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 25).

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 24).

During programming (see Programming the AS5040), 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)

ams Datasheet

[v2-12] 2017-Jun-20

Page 21

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