GPIO

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, the LabJack U3 included, 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`	required	Target level: `0` or `1`. Do not pass a string such as `"high"`: the drivers compare the pin reading with the integer `1`
`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
LabJack U3	Software polling	100 Hz (10 ms interval)
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
LabJack U3	FIO4-FIO7, EIO0-EIO7, CIO0-CIO3
MCC USB-202	DIO0-DIO7	5V TTL
FTDI FT232H / FT2232H	ADBUS0-7, ACBUS0-7 (16 bits per channel)	3.3V
FTDI FT4232H	8 pins per channel	3.3V

Pin Naming

LabJack T7:

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

LabJack U3:

FIO0-FIO3 are not GPIO pins. On a U3-HV they are fixed high-voltage analog inputs, and the driver refuses them. Read them with an ADC net on AIN0-AIN3.
input() reads the pin without a change to its direction. output() sets the pin to output.
FIO4-FIO7 and EIO0-EIO7 are also analog inputs. A GPIO call sets the pin to digital mode.
The EIO and CIO lines are on the DB15 connector of the U3.

MCC USB-202:

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

Multi-channel FTDI adapters

An FTDI net takes its channel from params.interface on the net record, accepting A-D or 0-3. Set it with lager nets add --interface. A net with no interface uses channel A, the only choice on a single-channel FT232H.

Part	Channels	Usable for GPIO
FT232H	1 (A)	A
FT2232H	2 (A, B)	A, B
FT4232H	4 (A-D)	A-D

GPIO runs as asynchronous bitbang and needs no MPSSE engine, so every channel the part has is usable. Note the pin width differs: the FT232H and FT2232H expose ADBUS0-7 plus ACBUS0-7 (16 bits), while each FT4232H channel is 8 pins wide. See Nets for how channels are assigned across net types on one chip.

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() takes an integer level (0 or 1) and 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

Getting Started

Development

Power & Simulation

Measurement

I/O & Communication

Utilities

Import

Methods

Method Reference

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

`input()`

`output(level)`

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

Examples

Read Button State

Control LED

Wait for Interrupt

Button-Controlled LED

Toggle Output

Supported Hardware

Pin Naming

Multi-channel FTDI adapters

Notes

​Import

​Methods

​Method Reference

​Net.get(name, type=NetType.GPIO)

​input()

​output(level)

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

​Examples

​Read Button State

​Control LED

​Wait for Interrupt

​Button-Controlled LED

​Toggle Output

​Supported Hardware

​Pin Naming

​Multi-channel FTDI adapters

​Notes

Import

Methods

Method Reference

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

`input()`

`output(level)`

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

Examples

Read Button State

Control LED

Wait for Interrupt

Button-Controlled LED

Toggle Output

Supported Hardware

Pin Naming

Multi-channel FTDI adapters

Notes