STMPE16M31 datasheet(49/85 Pages) STMICROELECTRONICS

部件名	STMPE16M31

功能描述	S-Touch® 16/24-channel touchkey controller with PWM and ratio engines

PDF	85 Pages

Scroll/Zoom	100%

制造商	STMICROELECTRONICS [STMicroelectronics]

网页	http://www.st.com

标志

49 / 85 page

STMPE16M31, STMPE24M31

Touch sensor controller

Doc ID 16174 Rev 4

49/85

Figure 14.

Touch sensing module flowchart

13.1

Sampling rate calculation

The capacitive sensor operates with a 2 MHz base clock, a single capacitive sensor scans

up to 24 active channels.

The SCLK_DIV divides the sensor clock by 64-1024, giving 2 kHz-32 kHz sensor clock.

For capacitive sensing, a PRBS sequence is utilized to remove the effect of surrounding

noise. This PRBS has an average value of 4.5.

The effective total sampling rate is thus 2 kHz-32 kHz divided by 4.5, giving 440 Hz – 7 kHz.

If all 24 channels of capacitive sensors are active, the channel conversion rate is thus

440 Hz/24 = 18.3 Hz (Min), 7 kHz/24 =296 Hz (Max)

Using the maximum MAF setting (18 remove 2), the maximum filtered channel output rate is

296 Hz/18 = 16 Hz.

13.2

Sensor resolution

The capacitive sensor hardware in the STMPExxM31 devices has a sensitivity of 15 fF and

a range of 512 steps giving it a dynamic range of 7.5 pF.

Obsolete

Product(s)

- Obsolete

Product(s)

STMPE16M31 数据表(PDF) 49 Page - STMicroelectronics