Preliminary

TTP229

09’/12/22

Page 13 of 19

Ver : 1.1

5. Wake-up sampling rate and sampling length at sleep mode

The TTP229 has two kinds of sampling rate at sleep mode. These are 8Hz and 64Hz. The two

connected to VSS, it selected the 64Hz sampling rate. Another it is 8Hz that is not used resistor

connected to VSS. The 8Hz sampling is the default.

And TTP229 has two kinds of sampling length at sleep mode. They are 4ms and 2ms that are selected

Another it is 2ms that TP6 pin has used a high-value resistor connected to VSS.

Wake-up sampling timing and length in the sleep mode：

or

8Hz=>125ms

4.0ms or 2.0ms

64Hz=>15.6ms

clock

Detect

Wake-up

6. Maximum key-on time

If some objects cover in the sense pad, and causing the change quantity enough to be detected. To

prevent this, the TTP229 sets a timer to monitor the detection. The timer is the maximum key-on time.

It is set about 80sec at 3V. When the detection is over the timer, the system will return to the power-on

initial state, and the output becomes inactive until the next detection. The function is set via a

resistor, it is set disable the maximum key-on time, then the key acts infinitely, this is the default.

Another it is set enable the maximum key-on time that has a resistor.

If the system needs to use the maximum key-on time enable and 2-wires serial output interface

function, it only uses always polling data for 2-wires serial output interface.

7. Built-in regulator with external enable/disable

The capacitive sensing touch pad IC needs stable power. So the TTP229 built in regulator in the chip.

It can make the internal power to keep up steady. And the sensitivity detection is normal for chip. And

the stable power can avoid sensitivity anomalies and false detections.

The built in regulator can be set enable or disable by the REGEN pin. When REGEN pin connected to

VDD or floated, it is enabled regulator. The REGEN pin connects to VSS, it is disabled regulator.

When the internal regulator is disabled, the VREG pin must be connected to external VDD.

8. Auto calibration function

The TTP229 includes a full auto-calibration function. After the device is powered-on, it will

calibrate the initial condition of environment first. On the duration time all the functions are disabled,

so do not operate. Then the system is into stand-by mode. And all keys are not detected touch more

than about 4 seconds, then the system do re-calibration automatically. The procedure is fixed and

repeated. By implementing this feature the system can catch the conditions of environment changing.

And let operation of the system is normal.