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Momentary/Latching Switch with Debouncing

Generic class for handling momentary/latching switches with debouncing. Inspired by Mutable Instruments Switch classes.

Features:

Debounced button input
Rising/falling edge detection
Press duration tracking
Toggle or momentary modes
Normal or inverted polarity

Usage:

import nimphea/hid/switch

var button: Switch
button.init(D0())  # Simple momentary button on pin D0

while true:
  button.debounce()
  
  if button.risingEdge():
    echo "Button pressed!"
  
  if button.pressed():
    echo "Button held for ", button.timeHeldMs(), " ms"
  
  delayMs(1)

Imports

nimphea

Types

GpioPull {.importcpp: "daisy::GPIO::Pull", size: 4.} = enum PULL_NOPULL, ## No pull resistor PULL_UP, ## Pull-up resistor (default) PULL_DOWN ## Pull-down resistor: GPIO pull-up/pull-down configuration Source Edit
Switch {.importcpp: "daisy::Switch", header: "hid/switch.h".} = object: Debounced switch/button handler Source Edit
SwitchPolarity {.importcpp: "daisy::Switch::Polarity", size: 4.} = enum POLARITY_NORMAL, ## HIGH = pressed POLARITY_INVERTED ## LOW = pressed (default, common with pull-ups): Switch polarity (which state is "pressed") Source Edit
SwitchType {.importcpp: "daisy::Switch::Type", size: 4.} = enum TYPE_TOGGLE, ## Toggle/latching switch TYPE_MOMENTARY ## Momentary pushbutton (default): Switch behavior type Source Edit

Procs

proc Debounce(this: var Switch) {.importcpp: "#.Debounce()", header: "hid/switch.h", ...raises: [], tags: [], forbids: [].}: Source Edit
proc debounce(sw: var Switch) {....raises: [], tags: [], forbids: [].}: Update switch state with debouncing

Call this regularly (e.g., every 1ms) to update the switch state. Must be called for edge detection and timing to work correctly.

Example:

while true: button.debounce() # Check button state... delayMs(1)
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proc fallingEdge(sw: Switch): bool {....raises: [], tags: [], forbids: [].}: Check if button was just released

Returns: true for one cycle when button transitions from pressed to released

Example:

if button.fallingEdge(): echo "Button released!"
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proc FallingEdge(this: Switch): bool {.importcpp: "#.FallingEdge()", header: "hid/switch.h", ...raises: [], tags: [], forbids: [].}: Source Edit
proc Init(this: var Switch; pin: Pin; update_rate: cfloat = 0.0) {. importcpp: "#.Init(@)", header: "hid/switch.h", ...raises: [], tags: [], forbids: [].}: Source Edit
proc Init(this: var Switch; pin: Pin; update_rate: cfloat; t: SwitchType; pol: SwitchPolarity; pu: GpioPull) {.importcpp: "#.Init(@)", header: "hid/switch.h", ...raises: [], tags: [], forbids: [].}: Source Edit
proc init(sw: var Switch; pin: Pin) {....raises: [], tags: [], forbids: [].}: Initialize switch with default settings (momentary, inverted, pull-up)

Parameters:

pin - GPIO pin for the switch

Example:

var button: Switch button.init(D0())
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proc init(sw: var Switch; pin: Pin; switchType: SwitchType; polarity: SwitchPolarity; pull: GpioPull) {....raises: [], tags: [], forbids: [].}: Initialize switch with full configuration

Parameters:

pin - GPIO pin for the switch

switchType - TYPE_MOMENTARY or TYPE_TOGGLE

polarity - POLARITY_NORMAL or POLARITY_INVERTED

pull - PULL_NOPULL, PULL_UP, or PULL_DOWN

Example:

var button: Switch button.init(D0(), TYPE_MOMENTARY, POLARITY_INVERTED, PULL_UP)
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proc pressed(sw: Switch): bool {....raises: [], tags: [], forbids: [].}: Check if button is currently held down

Returns: true while button is pressed (after debouncing)

Example:

if button.pressed(): echo "Button is down"
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proc Pressed(this: Switch): bool {.importcpp: "#.Pressed()", header: "hid/switch.h", ...raises: [], tags: [], forbids: [].}: Source Edit
proc rawState(sw: var Switch): bool {....raises: [], tags: [], forbids: [].}: Read raw button state without debouncing

Returns: true if button is physically pressed (without debounce)

Note: Usually you want pressed() instead
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proc RawState(this: var Switch): bool {.importcpp: "#.RawState()", header: "hid/switch.h", ...raises: [], tags: [], forbids: [].}: Source Edit
proc RisingEdge(this: Switch): bool {.importcpp: "#.RisingEdge()", header: "hid/switch.h", ...raises: [], tags: [], forbids: [].}: Source Edit
proc risingEdge(sw: Switch): bool {....raises: [], tags: [], forbids: [].}: Check if button was just pressed

Returns: true for one cycle when button transitions from released to pressed

Example:

if button.risingEdge(): echo "Button pressed!"
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proc TimeHeldMs(this: Switch): cfloat {.importcpp: "#.TimeHeldMs()", header: "hid/switch.h", ...raises: [], tags: [], forbids: [].}: Source Edit
proc timeHeldMs(sw: Switch): float {....raises: [], tags: [], forbids: [].}: Get how long the button has been held

Returns: Time in milliseconds that button has been pressed (0 if not pressed)

Example:

if button.pressed(): echo "Held for ", button.timeHeldMs(), " ms"
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