GPIO & Digital I/O

Digital pins are one thin class: new GPIO(pin, flags) configures the pin, and each method — set, get, toggle — lowers to exactly one Zephyr call. The flags are Zephyr’s own GPIO_* tokens verbatim. There is no pinMode() and no Wiring-style pin renumbering.

Basic Usage

import { GPIO } from '@typecad/hal';
import { LED, BUTTON } from '@typecad/board';

const led = new GPIO(LED, GPIO.OUTPUT | GPIO.OUTPUT_INIT_LOW);
const button = new GPIO(BUTTON, GPIO.INPUT | GPIO.PULL_UP);

led.set(true);          // drive the pin
if (button.get()) {     // read it
  led.toggle();         // atomic toggle
}

Construction Carries the Configuration

Combine the flags with | — they are the flags gpio_pin_configure_dt receives:

Token	Zephyr equivalent	Meaning
`GPIO.INPUT` / `GPIO.OUTPUT`	`GPIO_INPUT` / `GPIO_OUTPUT`	Direction
`GPIO.OUTPUT_INIT_LOW` / `GPIO.OUTPUT_INIT_HIGH`	`GPIO_OUTPUT_INIT_LOW` / `GPIO_OUTPUT_INIT_HIGH`	Output’s initial level, set atomically — no configure-then-write glitch
`GPIO.PULL_UP` / `GPIO.PULL_DOWN`	`GPIO_PULL_UP` / `GPIO_PULL_DOWN`	Internal bias
`GPIO.OPEN_DRAIN` / `GPIO.OPEN_SOURCE`	`GPIO_OPEN_DRAIN` / `GPIO_OPEN_SOURCE`	Output topology (bus pins like I2C SDA)
`GPIO.DISCONNECTED`	`GPIO_DISCONNECTED`	Both buffers off

The pin argument takes a board pin export (LED, BUTTON, PB5), a number, or a Pin instance.

Output Operations

set(value) drives the pin. On a pin with a board devicetree binding (LED, BUTTON) the level is logical: set(true) means “LED on”, and the node’s GPIO_ACTIVE_LOW polarity is honored for you.

toggle() is the driver’s atomic toggle — not a read-then-write.

Input Operations

get() reads the logical level. It is safe in a bare expression:

if (button.get()) { /* ... */ }

⚙️ Advanced details — the fused configure

The one-time configure is fused into the read’s lowering as a single statement-expression, so the pin is correctly configured even at a call site where a leading setup statement would be dropped (an if-condition, a comparison operand).

Interrupts

Attach with a GPIO.INT_* token and a handler; detach with offInterrupt():

button.onInterrupt(GPIO.INT_EDGE_FALLING, () => { pressed = true; });
// …
button.offInterrupt();

Handlers run in interrupt context and the ISR-safety rules apply — see Hardware Events.

API Reference

Member	Description
`new GPIO(pin, flags)`	Configure at construction; `flags` are `GPIO.*` tokens combined with `\\|`.
`set(value)`	Drive the pin (logical level on devicetree-bound pins).
`get()`	Read the pin (logical level).
`toggle()`	Atomic toggle.
`onInterrupt(intFlags, fn)`	Attach an interrupt with a `GPIO.INT_*` token.
`offInterrupt()`	Detach the interrupt.

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