AS5261

Datasheet - Application In form atio n

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Due to the programming over the output pin the device will initially start in the communication mode. In this mode the digital angle value can be

read with a specific protocol format. It is a bidirectional communication possible. Parameters can be written into the device. A programming of the

device is triggered by a specific command. With another command (pass2func) the device can be switched into operation mode. In case of a

programmed user lock bit the AS5261 automatically starts up in the functional operation mode. No communication of the specific protocol is

possible after this.

A standard half duplex UART protocol is used to exchange data with the device in the communication mode.

9.2.1 UART Interface for Programming

The AS5261 uses a standard UART interface with a byte for address and two bytes for the data content. The read or write mode is selected in

the first byte. An even parity for every byte. The timing (baudrate) is selected by the AS5261 over an initial command from the master. The baud

rate register can be read and overwritten. The keep synchronization it AS5261 synchronizes art every Start bit. This happens during a standard

write access 3 times.

A time out function detects not complete commands and resets the AS5261 UART after the timeout period.

9.2.2 Frame Organization

Each frame is composed by 24 bits. The first byte (Address or Command) of the frame specifies the read/write operation with the register

address or is used for a command. 16 data bits contains the communication data. There will be no operation in case of the usage of a not

specified CMD. The UART programming interface block of the AS5261 can operate in slave communication or master communication mode. In

the slave communication mode the AS5261 receives the data. The programming tool is the driver of the single communication line. In case of the

master comunication mode the AS5261 transmits data in the frame format. The single communication line can be pulled down by the AS5261.

Table 11. OTP Commands and Communication

Possible Interface

Commands

Address / Command

AS5X63 Communication

Mode

Description

WRITE

0x00-0x0F (OTP)

0x10-0x1F (SFR)

0x20-0xFF (Special Mode)

SLAVE

Write related to the address the user data

READ

0x00-0x0F (OTP)

0x10-0x1F (SFR)

0x20-0xFF (Special Mode)

SLAVE and MASTER

Read related to the address the user data

FUSE

0x22+ key

SLAVE

Command for permanent programming

PASS2FUNC

0x23+ key

SLAVE

Change operation mode from communication to

operation