as5055 austriamicrosystems, as5055 Datasheet - Page 9

• Manufacturer Part Number: as5055
• Description: Low Power 12 Bit Magnetic Rotary Encoder
• Manufacturer: austriamicrosystems

AS5055
Data Sheet – SPI Communication
10 SPI Communication
The transmitted data consists of 14 bit data, an Error-Flag and a Parity bit. When writing data to the chip, the Error-
Flag is not applicable. The Parity is generated from the upper 15 bit and forms an even parity over the whole frame.
The Error-Flag indicates that a failure occurred in a previous transmission.
10.1 Command Package
Every command sent to the AS5055 is represented with the following layout.
10.2 Read Package (Value Read from AS5055)
The read frame always contains two alarm bits, the error and parity flags and the addressed data of the previous read
command.
10.3 Write Data Package (Value Written to AS5055)
The write frame is compatible to the read frame and contains two additional bits, the don’t care and parity flag.
If the previous command was a write command a second package has to be transmitted.
www.austriamicrosystems.com
Bit
Bit Definition & Description
RWn
Address
PAR
Bit Definition & Description
Data
EF
PAR
Bit Definition & Description
Data
PAR
Bit
Bit
MSB
RWn
MSB
MSB
14
14
14
14 bit data to write to former selected address
Parity bit (EVEN)
13
Indicates read or write command
14 bit address code
Parity bit (EVEN)
14 bit addressed data
Error flag indicating a transmission error in a previous host transmission
Parity bit (EVEN)
13
13
12
12
12
11
11
11
10
10
10
Command Package
Data <13:0>
Data <13:0>
9
9
Read Package
9
Data Package
Address<13:0>
Revision 1.2
8
8
8
7
7
7
6
6
6
5
5
5
4
4
4
3
3
3
2
2
2
Don’t
care
1
EF
1
1
9 – 22
PAR
LSB
LSB
PAR
PAR
LSB