Set the drive strength of a given GPIO pin. The higher the drive strength, the more current can be sourced/sunk from the pin. The exact maximum depends on the power domain of the pin and how much current other pins in that domain are consuming.
#### Syntax
`gpio.set_drive(pin, strength)`
#### Parameters
-`pin`, a valid GPIO pin number.
-`strength` the drive strength to set, one of
-`gpio.DRIVE_0` weakest drive strength
-`gpio.DRIVE_1` stronger drive strength
-`gpio.DRIVE_2` default drive strength
-`gpio.DRIVE_DEFAULT` default drive strength (same as `DRIVE_2`)
-`gpio.DRIVE_3` maximum drive strength
#### Returns
`nil`
#### Example
```lua
gpio.set_drive(4,gpio.DRIVE_3)
```
## gpio.trig()
## gpio.trig()
Establish or clear a callback function to run on interrupt for a GPIO.
Establish or clear a callback function to run on interrupt for a GPIO.