A “pin” is an input or output on the Smoothieboard.
In a lot of cases (step/direction for external stepper motors, button inputs), you can use any pin for any use.
In other cases, a given pin is tied to a given peripheral on the board.
See Pinout to learn about which pins are where.
You can have a pin’s output inverted by adding a ! after this pin’s number in the config line, example:
my_pin_name 19!
There are other modifiers for pins:
| Modifier | Symbol | Description |
|---|---|---|
| Invert pin | ! |
Exclamation mark |
| Open drain | o |
Lowercase O letter |
| Pull up | ^ |
Caret, Shift+6 on QWERTY keyboards (Default on most pins) |
| Pull down | v |
Lowercase v letter |
| No pullup | - |
Minus sign |
| Repeater mode | @ |
At / Arobase sign |
| No modifier | If you do not set any option/modifier for your pin, it will be in pullup mode as if it had ^ specified |
[!WARNING] Some pins have hardware on the board itself, enforcing a given configuration.
The main example of this is the endstop inputs, which have on-board pull-up resistors, meaning trying to deactivate pull-ups in configuration (
-for them) will not work (configuration cannot deactivate/remove physically present pull-up resistors, it can only act on pull-up pin-configuration peripherals “inside” the chip).