|Top Previous Next|
Gets or sets which input port pins have pull-up resistors.
A bit mask identifying the port pins that have input pull-up resistors.
Setting a bit of the pullup property to 1 adds a pull-up resistor to the corresponding port pin if it is an input. This allows the input pin to be used with buttons and switches to ground without external pull-up resistors. This setting is ignored on pins that are outputs. The pull-up resistor is about 27k to the 3.3V supply voltage.
Each port pin has a corresponding bit value, as shown in the table:
To enable pull-up resistors on specific pins, OR together their corresponding bit values and assign the result to pullup.