10.7 Internal Pull up Resistors

The ATWILC3000-MR110xA provides programmable pull-up resistors on various pins. The purpose of these resistors is to keep any unused input pins from floating, which can cause excess current to flow through the input buffer from the VDDIO supply. Any unused pin on the device must leave these pull-up resistors enabled so the pin will not float.

The default state at power-up is with the pull-up resistor enabled. However, any pin that is used must have the pull-up resistor disabled. This is because if any pins are driven to a low level while the device is in the low power sleep state, current will flow from the VDDIO supply through the pull-up resistors, increasing the current consumption of the module.

The current through any pull-up resistor that is being driven low will be VDDIO/100k because the value of the pull-up resistor is approximately 100 kΩ. For VDDIO = 3.3V, the current is approximately 33µA. Pins that are used and have had the programmable pull-up resistor disabled must always be actively driven to either a high or low level and not be allowed to float.