API Input

Keyboard and button input functions.

picocalc.input

Functions

picocalc.input.update()

Polls the keyboard for new input events. Call once per frame before reading button or character state.

update() also services HTTP/TCP/sound callbacks, the system menu and dev commands.

• Parameters: None
• Returns: None

picocalc.input.update()

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picocalc.input.getButtons()

Returns the current bitmask of held buttons.

• Parameters: None
• Returns: (number) Bitmask of currently pressed buttons

local buttons = picocalc.input.getButtons()
if buttons & picocalc.input.BTN_UP ~= 0 then
    -- Up button is held
end

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picocalc.input.getButtonsPressed()

Returns the bitmask of buttons that were pressed this frame (edge detection, not held).

• Parameters: None
• Returns: (number) Bitmask of buttons pressed this frame

local pressed = picocalc.input.getButtonsPressed()
if pressed & picocalc.input.BTN_ENTER ~= 0 then
    -- Enter was just pressed
end

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picocalc.input.getButtonsReleased()

Returns the bitmask of buttons that were released this frame.

• Parameters: None
• Returns: (number) Bitmask of buttons released this frame

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picocalc.input.getButtonsRepeated()

Like getButtonsPressed(), but buttons held past the repeat delay also produce synthetic repeat edges (see setRepeat()). Useful for menus that should scroll while a button is held.

• Parameters: None
• Returns: (number) Bitmask of pressed edges plus synthetic repeat edges

picocalc.input.setRepeat(400, 80)  -- start repeating after 400ms, then every 80ms
local pressed = picocalc.input.getButtonsRepeated()
if pressed & picocalc.input.BTN_DOWN ~= 0 then
    selection = selection + 1  -- scrolls while held
end

---

picocalc.input.setRepeat(delay_ms [, rate_ms])

Configures key auto-repeat for getButtonsRepeated().

• Parameters:
  • delay_ms (number): Milliseconds a button must be held before repeating starts. 0 disables auto-repeat.
  • rate_ms (number, optional): Milliseconds between repeat edges (default 80, minimum 1).
• Returns: None

picocalc.input.setRepeat(400)      -- repeat every 80ms after a 400ms hold
picocalc.input.setRepeat(0)        -- disable auto-repeat

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picocalc.input.getChar()

Returns the last ASCII character typed, if any.

• Parameters: None
• Returns: (string or nil) Single-character string, or nil if no character was typed this frame

local ch = picocalc.input.getChar()
if ch then
    text = text .. ch
end

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picocalc.input.getRawKey()

Returns the raw STM32 keycode from the keyboard controller.

• Parameters: None
• Returns: (number) Raw key code

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picocalc.input.clearState()

Clear all button and key input state. Resets pressed, released, and held button buffers, queued pollEvent events and isKeyDown state. Useful when returning from modal dialogs or menus to prevent stale input.

• Parameters: None
• Returns: None

-- After closing a dialog, clear stale input
picocalc.input.clearState()

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picocalc.input.pollEvent()

Pops the oldest keyboard event, or nil when none is queued. Events are filled by update() in the order keys were pressed and released, so taps shorter than a frame and several characters in one frame are all reported.

• Returns: (table or nil) {type, key, char, mods, button, repeat}:
  • type: "down", "up" or "char"
  • key: ASCII for printable keys, else the keyboard code (as getRawKey())
  • char: the character ("char" events only)
  • mods: BTN_SHIFT/BTN_CTRL/BTN_ALT/BTN_FN held at the event
  • button: the BTN_* constant for keys that have one
  • repeat: true for events produced by holding the key (read as ev["repeat"])

Independent of getChar()/getButtons*(). 16 events are kept (the oldest is dropped); a new app starts with an empty queue.

picocalc.input.update()
for ev in picocalc.input.pollEvent do
    if ev.type == "char" then text = text .. ev.char end
end

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picocalc.input.isKeyDown(k)

True while a key is held. k is a one-character string ("w"; letters ignore case) or an integer keycode as pollEvent reports it. Updated by update(). Reliable for buttons (arrows, Enter, Esc, F-keys, modifiers); letters and shifted symbols depend on the keyboard reporting their release (pending hardware confirmation). clearState() clears a key that sticks.

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Button Constants

Bitmask values for button states:

Constant	Description
picocalc.input.BTN_UP	D-pad Up
picocalc.input.BTN_DOWN	D-pad Down
picocalc.input.BTN_LEFT	D-pad Left
picocalc.input.BTN_RIGHT	D-pad Right
picocalc.input.BTN_ENTER	Enter key
picocalc.input.BTN_ESC	Escape key
picocalc.input.BTN_MENU	Menu key (system overlay, auto-handled)
picocalc.input.BTN_F1	F1 key
picocalc.input.BTN_F2	F2 key
picocalc.input.BTN_F3	F3 key
picocalc.input.BTN_F4	F4 key
picocalc.input.BTN_F5	F5 key
picocalc.input.BTN_F6	F6 key
picocalc.input.BTN_F7	F7 key
picocalc.input.BTN_F8	F8 key
picocalc.input.BTN_F9	F9 key
picocalc.input.BTN_BACKSPACE	Backspace key
picocalc.input.BTN_TAB	Tab key
picocalc.input.BTN_DEL	Delete key
picocalc.input.BTN_SHIFT	Shift modifier (left or right)
picocalc.input.BTN_CTRL	Ctrl modifier
picocalc.input.BTN_ALT	Alt modifier
picocalc.input.BTN_FN	Fn/Symbol modifier