Datasheet

9. Notes On Interfacing to the ATWINC15x0-MR210xB

9.1 Programmable Pull Up Resistors

The ATWINC15x0-MR210xB 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 module pin on the ATWINC15x0-MR210xB

should leave these pull up resistors enabled so the pin will not float. The default state at power-up is for

the pull up resistor to be enabled. However, any pin that is used should have the pull up resistor disabled.

The reason for this is that if any pins are driven to a low level while the ATWINC15x0-MR210xB 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. Since the value of the pull up resistor is approximately 100KΩ,

the current through any pull up resistor that is being driven low will be VDDIO/100K. For VDDIO = 3.3V,

the current through each pull up resistor that is driven low would be approximately 3.3V/100K = 33µA.

Pins which are used and have had the programmable pull up resistor disabled should always be actively

driven to either a high or low level and not be allowed to float.

ATWINC15x0

Notes On Interfacing to the ATWINC15x0-MR210xB

Datasheet

DS70005304C-page 27