Dear All,I would like to know which is the better GPIO configuration to drive a LED for extremely low power consumption. We have a board with nRF52832 SoC with GPIO connected to a LED catode and LED anode connected through resistor to a voltage of power supply (VDD, the same voltage power supply as nRF52832 SoC). In our application LED will be off for the most of the time.
Is it better to configure GPIO as input with input buffer disconnected and change the pin configuration in output low when we want to switch-on the led or configure GPIO as output high and change the pin configuration in output low when we want to switch-on the LED?
In other words, I wuold like to know which is the better configuration to assure minimal current draw during period in which led will be off. With GPIO configured as input with input buffer disconnect there should be no any "leakage" current flowing on the led because circuit is open whereas if we configure GPIO as ouput high the catode of the led it should be at the same voltage potential that the anode (i.e. VDD) but considering that VOH,SD could have voltage as VDD-0.4V this solution seems to be most dangerous respect the other. Please can you confirm this?
There's no difference. As you pointed out, cathode will be connected to VDD, there is no path to leak out. Also, you can configure pin as H0D1 (high drive low, disconnected high).