AS5262

Datasheet - Application In form atio n

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9.2 Programming the AS5262

The AS5262 programming is a one-time-programming (OTP) method, based on polysilicon fuses. The advantage of this method is that no

additional programming voltage is needed. The internal LDO provides the current for programming.

The OTP consists of 128 bits; several bits are available for user programming. In addition factory settings are stored in the OTP memory. Both

regions are independently lockable by build in lock bits.

A single OTP cell can be programmed only once. Per default, the cell is “0”; a programmed cell will contain a “1”. While it is not possible to reset

a programmed bit from “1” to “0”, multiple OTP writes are possible, as long as only unprogrammed “0”-bits are programmed to “1”.

Independent of the OTP programming, it is possible to overwrite the OTP register temporarily with an OTP write command. This is possible only

if the user lock bit is not programmed.

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 AS5262 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 AS5262 uses a standard UART interface with an address byte and two data bytes. The read or write mode is selected with bit R/Wn in the

first byte. The timing (baudrate) is selected by the AS5262 over a synchronization frame. The baud rate register can be read and overwritten

(optional). Every start bit is used for synchronisation.

A time out function detects not complete commands and resets the AS5262 UART after the timeout period.

9.2.2 Frame Organization

Each frame is composed by 24 bits. The first byte of the frame specifies the read/write operation with the register address. 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

AS5262 can operate in slave communication or master communication mode. In the slave communication mode the AS5262 receives the data.

The programming tool is the driver of the single communication line. In case of the master communication mode the AS5262 transmits data in

the frame format. The single communication line can be pulled down by the AS5262.

The UART frame consists of 1 start bit (low level), 8 data bit, 1 even-parity bit and 1 stop bit (high level). Data are transferred from LSB to MSB

Figure 13. General UART Frame

Table 12. Bit Timing

Symbol

Parameter

Min

Typ

Max

Unit

Note

START

Start bit

1

TBIT

Dx

Data bit

1

TBIT

PAR

Parity bit

1

TBIT

STOP

Stop bit

1

TBIT

TSW

Slave/Master Switch Time

7

TBIT

D0

D1

D2

D3

D4

D5

D6

D7 par

start

stop