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AS6221T

Register Description

Datasheet

• PUBLIC

DS001032

• v1-00 • 2022-Apr-08

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6.3.2

Data Interface

A bus connection is created by connecting the open drain input/output lines SDA and SCL to the two

wire bus. The inputs of SDA and SCL feature Schmitt-trigger inputs as well as low pass filters in order

to suppress noise on the bus line. This improves the robustness against spikes on the two wire

interface.

Both fast transmission mode (1 kHz to 400 kHz) and high-speed transmission mode (1 kHz to

3.4 MHz) are employed to cover different bus speed settings.

Any data transfer transmits the MSB first and the LSB as last bit.

6.3.3

Bus Address

A slave address consists of seven bits, followed by a data direction bit (read/write operation). The

slave address can be selected from 8 different address settings by connecting the pin ADD0 and

ADD1 to an appropriate signal as summarized in Figure 29.

The ADD0 and the ADD1 pin must not be left unconnected.

The address selection with ADD1 is depending on the usage of the ALERT function (described in

chapter 6.3.8). In case the ALERT functionality is used, it must be connected via a pull up resistor to

VDD. In case the ALERT functionality is not used, the pin must be connected to either SCL or VSS

(refer to Figure 29 for details).

Figure 29:

I²C Address Select Configuration

ALERT / ADD1

Connection

ADD0 Connection

Alert

Functionality

Enabled

Device Address

(bin)

Device Address

(hex)

SCL

VSS

No

100 0100

0x54

SCL

VDD

No

100 0101

0x55

SCL

SDA

No

100 0110

0x56

SCL

SCL

No

100 0111

0x57

VSS

VSS

No

100 1000

0x58

VSS

VDD

No

100 1001

0x59

VSS

SDA

No

100 1010

0x5A

VSS

SCL

No

100 1011

0x5B

Pull up to VDD

VSS

Yes

100 1000

0x58

Pull up to VDD

VDD

Yes

100 1001

0x59

Pull up to VDD

SDA

Yes

100 1010

0x5A