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AS8530

Preliminary Data Sheet - A p p l i c a t i o n I n f o r m a t i o n

operates in permanent normal mode. Also possible is the external (outside of the module) control of the EN line via. VSUP signal as shown

below.

Figure 13. Permanent Normal Mode

8.7 Serial Port Interface

The interface is essentially used to trigger the window watchdog, to access test mode and read out diagnostic information for the AS8530. The

description of this interface and the protocol is explained below. Information on block status and errors can be displayed by diagnosis registers.

8.7.1 Device Configuration using 2-Wire Serial Port

The AS8530 device configuration register is programmed via a 2-wire Serial Programming Interface. EN/SCL is used as Serial Clock and TX/

SDA_IO is used as Serial Data. EN is used as clock input to access serial port registers in serial port mode. Also EN is used to control transition

from normal mode to standby/sleep mode. The TX input of the device will be multiplexed as following:

LIN TX for transmitting data from microcontroller on LIN bus

SDA_IO for Serial data input/output, this will be used for serially accessing data from configuration and status register

8.7.1.1 SP Frame

A frame is formed by first byte for command and address/configuration and following bit stream that can be formed by an integer number of

bytes. Command is coded RD/WR on the first bits, length of the transfer is indicated by LEN1, LEN2 bits while address is given on LSB 5 bits.

Table 15. Command Bits

Command Bits

Register Address or Transmission Configuration

RD/WR

LEN1

LEN2

A4

A3

A2

A1

A0

RD/WR

Command

<A4:A0>

Description

0

WRITE

ADDRESS

Writes data byte on the given starting address.

1

READ

ADDRESS

Read data byte from the given starting address.

Table 16. Transfer Length

LEN1

LEN2

Length

Description

001

Transfer consists of single Data phase. After completion of single Data phase device comes out of Serial

port interface.

0

1

2

Transfer consist of two Data phase.

1

0

4

Transfer consist of four Data phase.

1

1

8

Transfer consist of eight Data phase.

EN

VSUP

VSS

VCC

RESET

RX

TX

AS8530

MCU

+ 5V

LIN

+