ttp229

TonTouch TTP229 hardware driver for CircuitPython. Can detect up to 16 channels of touch input over a specialized 2-pin serial interface.

If using a Raspberry Pi Pico series microcontroller (RP2040/RP235x), this module will utilize a PIO state machine to read data from the TTP229 efficiently. Otherwise, it will use basic digitalio bit-banging to control the clock pin and read data over the serial interface.

To use this module, the TTP229 must be configured for 2-wire serial interface mode (not I2C). It can support either 8-key or 16-key mode and clock active-high/low depending on the parameters provided in the class constructor. By default, the module is configured for 16-key mode with an active-high clock.

See the device documentation for how best to configure your pins of the TTP229.

  • Author(s): Cooper Dalrymple

Implementation Notes

Hardware:

Software and Dependencies:

class ttp229.Mode

Enum-like class representing the possible modes of the TTP229.

KEY_16 = 1

16-keys mode

KEY_8 = 0

8-keys mode

class ttp229.TTP229(sdo: microcontroller.Pin, scl: microcontroller.Pin, mode: int = Mode.KEY_16, invert_clk: bool = False)

Driver for the TTP229-BSF serial interface capacitive touch sensor. The states of each touch input can be accessed after calling update() using the data value, the on_press and on_release callbacks, or by treating the object as a list (see example below).

import board
import ttp229
ttp = ttp229.TTP229(board.GP0, board.GP1)
ttp.update()
for i in range(len(ttp)):
    print("Touch input {:d} is {:s}".format(i, "on" if ttp[i] else "off")
Parameters:

  • sdo – Serial data pin

  • scl – Serial clock pin

  • mode – Key mode using a constant of the Mode enum

  • invert_clk – If using an active-low clock, set this parameter to True

property data: int

Return an integer with the state of each touch pad in binary-indexed format.

deinit() → None

Deinitialize the TTP229 and releases any hardware resources for reuse.

on_press: Callable[[int], None] = None

Callback which will be called when a press is detected during the update() method. The callback must include 1 integer parameter for the index of the touch input.

import board
import ttp229
ttp = ttp229.TTP229(board.GP0, board.GP1)
def pressed(index:int) -> None:
    print("Touch input {:d} was pressed".format(index))
ttp.on_press = pressed
on_release: Callable[[int], None] = None

Callback which will be called when a release is detected during the update() method. The callback must include 1 integer parameter for the index of the touch input.

import board
import ttp229
ttp = ttp229.TTP229(board.GP0, board.GP1)
def released(index:int) -> None:
    print("Touch input {:d} was released".format(index))
ttp.on_release = released
update() → bool

Update the touch input state.