Part Number:MSP432P401R
I have a MSP43P401R Launch Pad kit. I have configured Pin 4.7 as my ADC-0 Pin and am using it to read data from a filter which I have made myself.
The issue is that when the output of the filter is measured on the MSO, the signal is clear without noise/distortion.
However, when I connect this output of my filter to the ADC configure Pin 4.7, the same signal reduces in amplitude to a value far below the input signal value.
For instance, I have provided a 6Hz 100mVpp Sine wave to my filter designed as a LPF with Fc at 20Hz. The waveform is as shown below,the yellow wave is the output of the filter.
However, when the output is connected to P4.7(ADC0) pin this is the outcome,the yellow output signal line falls almost flat:
Certain points of clarification:
- The filter has been designed with a cut-off of 20Hz and is a 6th order filter with an amplification stage at its output. It has been tested separately and works.
- The ADC has been used without interrupt and the value from ADC14MEM0 register is read via a function call by polling.
- The function generator when connected directly at the ADC pin provides, a clear output signal without attenuation.
- I have attached a Coupling capacitor of value 1uF at the output of my filter to remove the DC offset.
What could be the cause of this deterioation?