The Capacitive Touch tutorial page on PJRC.COM (https://www.pjrc.com/capacitive-touch-tutorial/) links to a tutorial that Mohannad Rawashdeh did to document using the touch pins in Teensy LC, 3.1, 3.2, and 3.6. Unfortunately that tutorial is no longer there (https://mb-raw.blogspot.com/2018/02/...ive-touch.html).