AW9203

June 2018 V1.2

www.awinic.com.cn

13

Copyright © 2016 SHANGHAI AWINIC TECHNOLOGY CO., LTD

In AW9203, the CDC resolution is 12Bit. the sampling period can be set by control register. The capacitive

sample are send to DSP for further processing, including digital filtering, base-line compensation, touch and

gesture judge, and so on.

The capacitive sensitivity can be adjusted by REXT resistance. The bigger the REXT value, the higher the

sensitivity. By default, 10k

Ω to GND resistor is recommended.

Capacitor/

Data

Convertor

（CDC）

Digital Signal

Processor

（DSP）

Interrupt Logic

INTN

Output

Detection

Touch Pad

REXT

CINT

Sx

Figure 11

Functional Block of Capacitive Detection Circuit

When control bit GCR.SENE is 0, all capacitive touch detection circuit is reset. When control bit GCR.SENE

is high, the SLPR register control the enable/disable touch detection. If control bit SLPR.SLPx is 0, channel x

touch detection function is activated. If control bit SLPR.SLPx set to 1, channel x touch detection is disabled

to save power consumption.

9.5.1

Touch

Status and Interrupt

In AW9203 , the touch status can be read in register KEYST (0x31).

Touching status can generate the interrupt output on pin INTN, the interrupt enable control is defined by

register KINTER (0x03). There are 4 interrupt mode selection defined by control bit KINTER.KIMD[1:0].

-

KIMD[1:0] =00

interrupt generates when touch status changed

-

KIMD[1:0] =01

interrupt generates when touch status changed from 1 to 0

-

KIMD[1:0] =10

interrupt generates when touch status changed from 0 to 1

-

KIMD[1:0] =11

interrupt generates when touch status is 1

The INTN pin will be pulled to GND when interrupt generates. The interrupt status can be clear by reading the

9.5.2

Gesture Status

Besides for touch detection, AW9203 provides click gesture detection function, including slide gesture, single,

double and triple click. Once the predefined gesture is detected，interrupt can be generated if corresponding

interrupt enable bit is set in control register GIER. This function will help reduce programming on external MCU,

and

save the system power consumption, improve the usability.

The slide gesture detects the finger moving on the touchpad. When finger moves on the touchpad, the

capacitive change can be detected one by one and the gesture module can identify the order of touch key and

judge the slide gesture.

Register GSTR (0x20/0x21) defines the slide gesture.

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

0

KCODE1

0

KCODE2

0

KCODE3

0

0

0

0

KCODE1~3 define 3bit key code. The code can be 3(s1), 4(s2), 5(s3), 0(no key).