AS5045 12-BIT PROGRAMMABLE MAGNETIC ROTARY ENCODER

Revision 1.5

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Note: Pin 1 (MagINCn) and pin 2 (MagDECn) are active low via open drain output and require an external pull-up resistor. If

the magnetic field is in range, both outputs are turned off.

The two pins may also be combined with a single pull-up resistor. In this case, the signal is high when the magnetic field is

in range. It is low in all other cases (see Table 4 and Table 5).

5.2

Daisy Chain Mode

The Daisy Chain mode allows connection of several AS5045’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. An RC filter must be implemented between each PROG pin of device n and

DO pin of device n+1, to prevent then encoders to enter the alignment mode, in case of ESD discharge, long cables, 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 length of the

serial bit stream increases with every connected device, it is

n * (18+1) bits:

e.g. 38 bit for two devices, 57 bit for three devices, etc…

The last data bit of the first device (Parity) is followed by a dummy bit and the first data bit of the second device (D11), etc…

(see Figure 7)

Figure 6: Daisy Chain hardware configuration

D11

1

D10

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0

OCF

COF

LIN

Mag

INC

Mag

DEC

D11

D

18

8

Status Bits

Angular Position Data

t

DO valid

t

DO active

T

CLK/2

t

CLK FE

CSn

DO

CLK

123

Even

PAR

D9

D10

Angular Position Data

Figure 7: Daisy Chain mode data transfer