PSoC SAR

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aleung
Level 2
Level 2
10 sign-ins 5 replies posted 5 questions asked

I setup the PSoC 62S4 Kit  ADC , with 2 channels  as singled end, Vref=VDDA,  Vminus=VSSA.   When feed the Vplus with known signal (or voltage) , the voltage readings of the two channel is ok and as expected.      When I  disconnected the signal, i.e.  the Vplus open ended,   I got reading (as calculated) is fixed as 2.8V  .    Is this normal?  As I thought an open-ended Vplus  will get varying readings from time to time, or at least the level is not so high.   

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Vasanth
Moderator
Moderator
Moderator
250 sign-ins 500 solutions authored First question asked

Hi,

As the floating pin could get influenced numerous other factors which could dependent on the schematic, routing, voltages on adjacent pins and routes etc  it will be difficult to tell the voltage read on a floating pin. But you could check giving a known voltage on the ADC input from VSSA-VDDA as input to the ADC and see if they are properly getting converted. You can confirm  whether the ADC is working as expected from this.

Best Regards,
Vasanth 

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Vasanth
Moderator
Moderator
Moderator
250 sign-ins 500 solutions authored First question asked

Hi,

As the floating pin could get influenced numerous other factors which could dependent on the schematic, routing, voltages on adjacent pins and routes etc  it will be difficult to tell the voltage read on a floating pin. But you could check giving a known voltage on the ADC input from VSSA-VDDA as input to the ADC and see if they are properly getting converted. You can confirm  whether the ADC is working as expected from this.

Best Regards,
Vasanth 

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