I use S32K144, The ADC result is gotten with DMA interrupt. There is a problem about ADC, Could you help me ?
I found, When I disconnected the ADC1_SE0, which means the ADC annalog input is nothing, but I still can get the DMA interrupt, and the Digital output is nearly 5V. By the way, Vref_h = 5V, Vref_L = grand.
1.How can I know the ADC input is open circuit?
2.When a pin is not used as GPIO, the pull down can not be set.
Thank you very much!
Do you mean, If the pin ADC1_Se0 is enabled pull-down, when the PTA2 pin (in ADC1_SE0 function) is not connected,then the digital output is 0 voltage?
Thank you very much for your reply!
1. When the PTA2 pin (in ADC1_SE0 function) is not connected to any circuit, the pin is floating, and the state of the pin cannot be defined.
2. But the internal pull-down can be enabled in every function of the PTA2 pin, including ADC1_SE0.