AS5040-ASST View Datasheet(PDF) - austriamicrosystems AG
Part Name
Description
MFG CO.
'AS5040-ASST' PDF : 61 Pages View PDF
AS5040 â 10-Bit Absolute Angular Position Output
Daisy Chain Mode
The Daisy Chain mode allows connection of several AS5040âs
in series, while still keeping just one digital input for data
transfer (see âData INâ 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, etcâŠ
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), etcâŠ
(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:
âą Open the connection DO -> Prog during programming or
âą 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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