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GPIO API Reference

The GPIO (General Purpose Input/Output) API provides access to 32 programmable I/O pins that can be configured for digital or analog operations. Each pin supports voltages from -25V to +25V for inputs and 0 to 24V for outputs.

Accessing GPIO​

const gpio = tester.gpio;

GPIO Module Methods​

reset()​

Resets all GPIO pins to their default configuration.

await tester.gpio.reset();

Returns: Promise<void> / Awaitable[None]

digital(io)​

Access a specific GPIO pin for digital operations.

const pin = tester.gpio.digital(0);

Parameters:

  • io (number / int): GPIO pin number (0-31)

Returns: DigitalIO instance

analog(io)​

Access a specific GPIO pin for analog operations.

const pin = tester.gpio.analog(0);

Parameters:

  • io (number / int): GPIO pin number (0-31)

Returns: AnalogIO instance

hold()​

Holds (freezes) the current state of all GPIO pins. This allows buffering multiple write commands before applying them simultaneously.

await tester.gpio.hold();

Returns: Promise<SyncConfiguration> / Awaitable[SyncConfiguration] - Configuration with action: "hold"

note

Prevents external changes to GPIO states until release() is called. All write operations between hold() and release() are buffered.

release()​

Releases control of GPIO pins, applying all buffered writes simultaneously. This also sets the device as a slave.

await tester.gpio.release();

Returns: Promise<SyncConfiguration> / Awaitable[SyncConfiguration] - Configuration with action: "release"

DigitalIO Class​

configure_input(config) / config_input(config)​

Configures the pin as a digital input with custom thresholds.

await pin.configure_input({
  vil: 0.8,  // Input low threshold
  vih: 2.0   // Input high threshold
});

Parameters:

  • config (PartialDigitalInputConfiguration):
    • vil (number / float, required): Voltage input low threshold (-25 to 25V)
    • vih (number / float, required): Voltage input high threshold (-25 to 25V)

Returns: Promise<DigitalInputConfiguration> / Awaitable[DigitalInputConfiguration] - Full configuration including mode and direction

Exceptions:

  • Throws validation error if vil or vih is outside the range [-25, 25]

configure_output(config) / config_output(config)​

Configures the pin as a digital output with custom voltage levels and thresholds.

await pin.configure_output({
  value: true,      // Initial state
  vol: 0.0,         // Output low voltage
  voh: 3.3,         // Output high voltage
  vil: 0.8,         // Optional input low threshold
  vih: 2.0          // Optional input high threshold
});

Parameters:

  • config (PartialDigitalOutputConfiguration):
    • value (boolean | number / bool | int, required): Initial output state (true/1 = high, false/0 = low)
    • vol (number / float, required): Voltage output low level (0 to 24V)
    • voh (number / float, required): Voltage output high level (0 to 24V)
    • vil (number / float, optional): Voltage input low threshold (-25 to 25V)
    • vih (number / float, optional): Voltage input high threshold (-25 to 25V)

Returns: Promise<DigitalOutputConfiguration> / Awaitable[DigitalOutputConfiguration] - Full configuration

Exceptions:

  • Throws validation error if vol or voh is outside the range [0, 24]
  • Throws validation error if vil or vih is outside the range [-25, 25]
note

When vil and vih are omitted, they are automatically deduced from the given voh and vol parameters.

configure_open_drain(config) / config_open_drain(config)​

Configures the pin as an open-drain output (useful for I2C, 1-Wire, etc.).

await pin.configure_open_drain({
  value: true,
  vil: 0.8,
  vih: 2.0
});

Parameters:

  • config (PartialOpenDrainConfiguration):
    • value (boolean | number / bool | int, required): Initial state (true = floating/high-Z, false = low)
    • vil (number / float, required): Voltage input low threshold (-25 to 25V)
    • vih (number / float, required): Voltage input high threshold (-25 to 25V)

Returns: Promise<OpenDrainConfiguration> / Awaitable[OpenDrainConfiguration] - Full configuration

Exceptions:

  • Throws validation error if vil or vih is outside the range [-25, 25]

read()​

Reads the current logical state of the pin.

const state = await pin.read();
console.log("Pin is", state ? "HIGH" : "LOW");

Returns: Promise<boolean> / Awaitable[bool] - true for HIGH, false for LOW

write(value)​

Writes a logical value to the pin (must be configured as output).

await pin.write(true);   // Set HIGH
await pin.write(false);  // Set LOW
await pin.write(1);      // Set HIGH (numeric)
await pin.write(0);      // Set LOW (numeric)

Parameters:

  • value (boolean | number / bool | int): Value to write (true/1 = HIGH, false/0 = LOW)

Returns: Promise<boolean> / Awaitable[bool] - The written value as boolean

AnalogIO Class​

configure_input() / config_input()​

Configures the pin as an analog input for voltage measurement.

await pin.configure_input();

Returns: Promise<AnalogInputConfiguration> / Awaitable[AnalogInputConfiguration] - Configuration with mode "analog" and direction "input"

configure_output(value) / config_output(value)​

Configures the pin as an analog output and sets the initial voltage.

await pin.configure_output(3.3);  // Set to 3.3V

Parameters:

  • value (number / float): Initial output voltage (0 to 24V)

Returns: Promise<AnalogOutputConfiguration> / Awaitable[AnalogOutputConfiguration] - Full configuration

Exceptions:

  • Throws validation error if value is outside the range [0, 24]

read()​

Reads the current analog voltage at the pin.

const voltage = await pin.read();
console.log("Voltage:", voltage, "V");

Returns: Promise<number> / Awaitable[float] - Measured voltage in volts

write(value)​

Sets the analog output voltage (must be configured as analog output).

await pin.write(3.3);   // Set to 3.3V
await pin.write(5.0);   // Set to 5.0V
await pin.write(12.5);  // Set to 12.5V

Parameters:

  • value (number / float): Voltage to output (0 to 24V)

Returns: Promise<number> / Awaitable[float] - The set voltage

Exceptions:

  • Throws validation error if value is outside the range [0, 24]

Types​

DigitalInputConfiguration​

{
  mode: "digital",
  direction: "input",
  vil: number,  // -25 to 25V
  vih: number   // -25 to 25V
}

DigitalOutputConfiguration​

{
  mode: "digital",
  direction: "output",
  value: boolean,
  vol: number,   // 0 to 24V
  voh: number,   // 0 to 24V
  vil: number,   // -25 to 25V
  vih: number    // -25 to 25V
}

OpenDrainConfiguration​

{
  mode: "digital",
  direction: "open_drain",
  value: boolean,
  vil: number,  // -25 to 25V
  vih: number   // -25 to 25V
}

AnalogInputConfiguration​

{
  mode: "analog",
  direction: "input"
}

AnalogOutputConfiguration​

{
  mode: "analog",
  direction: "output",
  value?: number  // 0 to 24V
}

Notes​

  • All 32 pins support both digital and analog modes
  • Voltage range: -25V to +25V for inputs, 0 to 24V for outputs
  • Digital thresholds (vil/vih) can be set independently for precise logic level detection
  • Open-drain mode is ideal for protocols requiring external pull-ups (I2C, 1-Wire)
  • When writing digital values, both boolean and number (0/1) are accepted
  • Analog readings provide precise voltage measurements
  • Use hold() and release() for synchronized multi-pin operations