GPIO

Control digital input/output pins

Control digital input/output pins for digital signaling and control.

Import

from lager import Net, NetType

Methods

Method	Description
input()	Read digital pin state
output(level)	Set digital pin state
wait_for_level(level, ...)	Wait for pin to reach a target level

Method Reference

Net.get(name, type=NetType.GPIO)

Get a GPIO net by name.

from lager import Net, NetType

pin = Net.get('LED', type=NetType.GPIO)

Parameters:

Parameter	Type	Description
name	str	Name of the GPIO net
type	NetType	Must be NetType.GPIO

Returns: GPIO Net instance

input()

Read the digital state of the pin.

from lager import Net, NetType

pin = Net.get('BUTTON', type=NetType.GPIO)
state = pin.input()

if state:
    print("Pin is HIGH")
else:
    print("Pin is LOW")

Returns: int - 0 for LOW, 1 for HIGH

output(level)

Set the digital state of the pin.

from lager import Net, NetType

pin = Net.get('LED', type=NetType.GPIO)

# Set HIGH
pin.output(1)

# Set LOW
pin.output(0)

Parameter	Type	Description
level	int or str	0/1, “low”/“high”, “off”/“on”, “true”/“false”

wait_for_level(level, timeout=None, ...)

Wait for the pin to reach a target level. Blocks until the pin reads the specified level or the timeout expires.

The LabJack T7 uses hardware streaming at up to 20 kHz for fast edge detection. Other hardware uses software polling.

from lager import Net, NetType

pin = Net.get('INTERRUPT', type=NetType.GPIO)

# Wait for pin to go HIGH (block forever)
elapsed = pin.wait_for_level(1)
print(f"Pin went HIGH after {elapsed:.3f}s")

# Wait with timeout
try:
    elapsed = pin.wait_for_level(0, timeout=5.0)
    print(f"Pin went LOW after {elapsed:.3f}s")
except TimeoutError:
    print("Timed out waiting for pin")

Parameters:

Parameter	Type	Default	Description
level	int or str	required	Target level: 0/1, “low”/“high”, “off”/“on”
timeout	float or None	None	Maximum seconds to wait. None = wait forever.
scan_rate	int	20000	Sample rate in Hz (LabJack T7 only)
scans_per_read	int	2	Batch size per read (LabJack T7 only; lower = faster reaction)
poll_interval	float	0.01	Seconds between polls (non-LabJack hardware only)

Returns: float - Elapsed time in seconds until the level was detected

Raises: TimeoutError if the timeout expires before the target level is reached

Hardware-specific behavior:

Hardware	Method	Default Rate
LabJack T7	Hardware streaming (ljm.eStreamStart)	20,000 Hz
USB-202	Software polling	100 Hz (10 ms interval)

Examples

Read Button State

from lager import Net, NetType

button = Net.get('BUTTON', type=NetType.GPIO)

state = button.input()
if state:
    print("Button pressed")
else:
    print("Button released")

Control LED

from lager import Net, NetType

led = Net.get('LED', type=NetType.GPIO)

# Turn on
led.output(1)

# Turn off
led.output(0)

Wait for Interrupt

from lager import Net, NetType

irq_pin = Net.get('INTERRUPT', type=NetType.GPIO)

# Wait for interrupt (rising edge)
try:
    elapsed = irq_pin.wait_for_level(1, timeout=10.0)
    print(f"Interrupt detected after {elapsed:.3f}s")
except TimeoutError:
    print("No interrupt within 10 seconds")

Button-Controlled LED

from lager import Net, NetType
import time

button = Net.get('BUTTON', type=NetType.GPIO)
led = Net.get('LED', type=NetType.GPIO)

print("Press Ctrl+C to exit")

while True:
    try:
        if button.input():
            led.output(1)
        else:
            led.output(0)
        time.sleep(0.1)
    except KeyboardInterrupt:
        led.output(0)
        break

Toggle Output

from lager import Net, NetType
import time

output_pin = Net.get('SIGNAL', type=NetType.GPIO)

# Generate 10 pulses
for i in range(10):
    output_pin.output(1)
    time.sleep(0.5)
    output_pin.output(0)
    time.sleep(0.5)

Supported Hardware

Hardware	Pins	Logic Level
LabJack T7	FIO0-FIO7, EIO0-EIO7, CIO0-CIO3	3.3V
MCC USB-202	DIO0-DIO7	5V TTL

Pin Naming

LabJack T7:

Pin Input	Channel
0-7	FIO0-FIO7
8-15	EIO0-EIO7
16-19	CIO0-CIO3
"FIO0"-"FIO7"	FIO0-FIO7

MCC USB-202:

Pin Input	Channel
0-7	DIO0-DIO7
"DIO0"-"DIO7"	DIO0-DIO7

Notes

• GPIO nets work directly without enable()/disable() calls
• input() returns 0 or 1
• output() accepts integers (0/1) or strings (“high”/“low”, “on”/“off”, “true”/“false”)
• wait_for_level() blocks the calling thread until the target level is detected
• LabJack T7 wait_for_level() uses hardware streaming for sub-millisecond detection
• Net names must match those configured on the Lager Box