micropython-cap1296's Introduction

CAP1296

Micropython module for Microchip CAP1296 I2C touch controller. You should have a working knowledge of how the CAP1296 works, please check out its datasheet.

Examples

I'm using a NodeMCU with Micropython (FW 1.9.3). A minimal working example starts with this setup:

# SETUP
import machine
import cap1296

# NodeMCU I2C interface
i2c = machine.I2C(scl=machine.Pin(5), sda=machine.Pin(4), freq=400000)
tc = cap1296.CAP1296(i2c)  # touch controller

Then we can get the status of the CAP's sensor input register using the read_keys function like this.

# No multitouch, print keys status as a byte
keys_now, keys_before = 0, 0
while True:
    keys_now, keys_before = tc.read_keys(), keys_now

    if keys_now != keys_before:  # keys state changed
        print(keys_now)

This prints a byte of the keys status each time the input changes (note that the output might be different than below if the byte is printable).

b'\x00'  # no key pressed
b'\x01'  # key 0 pressed
b'\x00'
b'\x02'  # key 1 pressed
b'\x00'
b'\x04'  # key 2 pressed
...

If you want multitouch and a list of all currently pressed keys, try this:

# Multitouch enabled, print list of pressed keys
tc.enable_multitouch(True)

# same as in the example above
keys_now, keys_before = 0, 0
while True:
    keys_now, keys_before = tc.read_keys(as_list=True), keys_now

    if keys_now != keys_before:  # user input occured
        print(keys_now)

This gives you:

[]  # no key pressed
[0]  # key 0 pressed
[0, 1]  # key 0 and 1 pressed
[]  # no key pressed
[1]  # key 1 pressed
[0, 1, 2, 3, 4]  # keys 0 to 4 pressed