Set the digital output level of GPIO pins, with an optional hold mode that keeps the output asserted until interrupted.
Syntax
lager gpo [NETNAME] LEVEL [OPTIONS]
Arguments
| Argument | Description |
|---|
NETNAME | GPIO net name (optional if default is set). If omitted, lists all available GPIO nets. |
LEVEL | Output level (see below) |
Level Values
The following values are accepted (case-insensitive):
| Value | Result |
|---|
high, on, 1 | Set pin high |
low, off, 0 | Set pin low |
toggle | Invert current state |
Options
| Option | Description |
|---|
--box BOX | Lagerbox name or IP address |
--hold | Hold output state (keeps process alive until Ctrl+C) |
Usage
# Set pin high
lager gpo LED1 high --box my-lager-box
# Set pin low
lager gpo LED1 low
# Toggle pin state
lager gpo LED1 toggle
# Using numeric values
lager gpo LED1 1
lager gpo LED1 0
# List available GPIO nets (omit net name and level)
lager gpo --box my-lager-box
Hold Mode
The --hold flag keeps the process alive after setting the output level. The pin state is maintained until you press Ctrl+C. This is useful when you need to assert a signal for manual testing or when the pin state would otherwise be reset between CLI invocations.
# Hold reset line low until manually released
lager gpo RESET_N low --hold --box my-lager-box
# Press Ctrl+C to release
# Hold enable pin high during manual testing
lager gpo EN high --hold
# Press Ctrl+C when done
Supported Hardware
| Device | Pins | Voltage |
|---|
| LabJack T7 | FIO0-FIO7 | 3.3V logic |
| MCC USB-202 | DIO0-DIO7 (0-7) | 3.3V/5V TTL |
| Aardvark | 0-5 (SCL, SDA, MISO, SCK, MOSI, SS) | 3.3V |
| FT232H | 0-15 (AD0-AD7, AC0-AC7) | 3.3V |
Aardvark and FT232H GPIO support is currently disabled and may be re-enabled in a future release. LabJack T7 and MCC USB-202 are the active GPIO backends.
Aardvark Pin Mapping
The Aardvark I2C/SPI adapter exposes 6 GPIO pins on its 10-pin header. Pins can be specified by number or signal name:
| Pin | Name | Header Pin |
|---|
| 0 | SCL | 1 |
| 1 | SDA | 3 |
| 2 | MISO | 5 |
| 3 | SCK | 7 |
| 4 | MOSI | 8 |
| 5 | SS | 9 |
FT232H Pin Mapping
The FT232H provides 16 GPIO pins across two ports:
| Pins | Names | Description |
|---|
| 0-7 | AD0-AD7 | Port A data pins |
| 8-15 | AC0-AC7 | Port A control pins |
Examples
# Control an LED
lager gpo LED1 on --box lab-gw
sleep 1
lager gpo LED1 off --box lab-gw
# Toggle reset line
lager gpo RESET_N low
sleep 0.1
lager gpo RESET_N high
# Blink pattern
for i in {1..5}; do
lager gpo LED1 toggle
sleep 0.5
done
# Hold a signal during manual testing
lager gpo BOOT0 high --hold --box lab-gw
# Ctrl+C to release, then flash firmware
# Assert chip select for manual SPI debugging
lager gpo CS_N low --hold --box lab-gw
Notes
- GPO is for setting output pins only
- Use
lager gpi to read input pins
- Default net can be set with
lager defaults add --gpio-net
- Pin must be configured as output in net configuration
- Toggle reads current state and inverts it
- USB-202 channels can be specified as
0-7 or DIO0-DIO7
--hold keeps the process running; press Ctrl+C to release the pin and exit- Without
--hold, the output level is set and the command exits immediately; the pin retains its state until the next command
