From 7f1beb6c97916ebb8b323f01530368cff51601a8 Mon Sep 17 00:00:00 2001 From: Dan Halbert Date: Wed, 28 May 2025 16:01:39 -0400 Subject: [PATCH] improve keypad doc re RP2350 E-9 erratum --- shared-bindings/keypad/KeyMatrix.c | 8 ++++++++ shared-bindings/keypad/Keys.c | 6 ++++++ shared-bindings/keypad/__init__.c | 2 +- 3 files changed, 15 insertions(+), 1 deletion(-) diff --git a/shared-bindings/keypad/KeyMatrix.c b/shared-bindings/keypad/KeyMatrix.c index 8303645f20183..edb32c2c5c700 100644 --- a/shared-bindings/keypad/KeyMatrix.c +++ b/shared-bindings/keypad/KeyMatrix.c @@ -67,6 +67,14 @@ //| in the respective state for ``debounce_threshold`` times on average. //| Successive measurements are spaced apart by ``interval`` seconds. //| The default is 1, which resolves immediately. The maximum is 127. +//| +//| .. warning:: On Raspberry Pi RP2350, using ``columns_to_anodes=False`` +//| normally depends on the internal pull-down resistors. +//| This will not work, due to an RP2350 issue. +//| The easiest fix is simply to swap the ``row_pins`` and ```column_pins`` and to set +//| ``columns_to_anodes=True``. This requires no external components. +//| An alternative is to add external pull-downs of 8.2 kohms or less, but that will draw more current. +//| See the Warning in `digitalio` for more information. //| """ //| ... //| diff --git a/shared-bindings/keypad/Keys.c b/shared-bindings/keypad/Keys.c index 10ac81cf1fb63..64e8e51a67ded 100644 --- a/shared-bindings/keypad/Keys.c +++ b/shared-bindings/keypad/Keys.c @@ -69,6 +69,12 @@ //| in the respective state for ``debounce_threshold`` times on average. //| Successive measurements are spaced apart by ``interval`` seconds. //| The default is 1, which resolves immediately. The maximum is 127. +//| +//| .. warning:: On Raspberry Pi RP2350, using ``value_when_pressed=True`` and ``pull=True``, +//| to enable using the internal pull-down resistor, will not work, due to an RP2350 +//| hardware issue. Instead, wire the switch to be ``value_when_pressed=False``, or add +//| an external pull-down resistor of 8.2 kohms or less. +//| See the Warning in `digitalio` for more information. //| """ //| ... //| diff --git a/shared-bindings/keypad/__init__.c b/shared-bindings/keypad/__init__.c index b29de197262f4..b182e977829d1 100644 --- a/shared-bindings/keypad/__init__.c +++ b/shared-bindings/keypad/__init__.c @@ -65,7 +65,7 @@ MP_PROPERTY_GETTER(keypad_generic_events_obj, //| due to a GPIO hardware issue that causes excessive leakage current (~120uA). //| A pin can read as high even when driven or pulled low, if the input signal is high //| impedance or if an attached pull-down resistor is too weak (has too high a value). -//| See the warning in `digitalio` for more information. +//| See the warnings in `keypad.Keys`, `keypad.KeyMatrix`, and `digitalio` for workarounds and more information. //| //| .. jinja //| """ pFad - Phonifier reborn

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