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Diffstat (limited to 'docs/esp32/quickref.rst')
| -rw-r--r-- | docs/esp32/quickref.rst | 29 |
1 files changed, 21 insertions, 8 deletions
diff --git a/docs/esp32/quickref.rst b/docs/esp32/quickref.rst index b9ca0f8225..5cce96d687 100644 --- a/docs/esp32/quickref.rst +++ b/docs/esp32/quickref.rst @@ -751,20 +751,33 @@ APA102 (DotStar) uses a different driver as it has an additional clock pin. Capacitive touch ---------------- -Use the ``TouchPad`` class in the ``machine`` module:: +ESP32, ESP32-S2 and ESP32-S3 support capacitive touch via the ``TouchPad`` class +in the ``machine`` module:: from machine import TouchPad, Pin t = TouchPad(Pin(14)) t.read() # Returns a smaller number when touched -``TouchPad.read`` returns a value relative to the capacitive variation. Small numbers (typically in -the *tens*) are common when a pin is touched, larger numbers (above *one thousand*) when -no touch is present. However the values are *relative* and can vary depending on the board -and surrounding composition so some calibration may be required. - -There are ten capacitive touch-enabled pins that can be used on the ESP32: 0, 2, 4, 12, 13 -14, 15, 27, 32, 33. Trying to assign to any other pins will result in a ``ValueError``. +``TouchPad.read`` returns a value proportional to the capacitance between the +pin and the board's Ground connection. On ESP32 the number becomes smaller when +the pin (or connected touch pad) is touched, on ESP32-S2 and ESP32-S3 the number +becomes larger when the pin is touched. + +In all cases, a touch causes a significant change in the return value. Note the +returned values are *relative* and can vary depending on the board and +surrounding environment so some calibration (i.e. comparison to a baseline or +rolling average) may be required. + +========= ============================================== +Chip Touch-enabled pins +--------- ---------------------------------------------- +ESP32 0, 2, 4, 12, 13, 14, 15, 27, 32, 33 +ESP32-S2 1 to 14 inclusive +ESP32-S3 1 to 14 inclusive +========= ============================================== + +Trying to assign to any other pins will result in a ``ValueError``. Note that TouchPads can be used to wake an ESP32 from sleep:: |