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MPC5674F Differential ADC Test

Question asked by Umit Kayacik on Jan 15, 2016
Latest reply on Jan 18, 2016 by David Tosenovjan

Hi,

 

Currently working on testing MPC5674F's differential adc measuring capabilites. I simply test the DAN0+ and DAN0- with three resistor like below :

nbgoI.png

 

 

uint32_t CQueue_0[] =

{

    ( CHANNEL(96)  | B0 | MESSAGE_TAG(RFIFO0)       ),

    ( CHANNEL(10)  | B0 | MESSAGE_TAG(RFIFO0)       ),

    ( CHANNEL(11)  | B0 | MESSAGE_TAG(RFIFO0)       ),

    ( CHANNEL(12)  | B0 | MESSAGE_TAG(RFIFO0)       ),

    ( CHANNEL(13)  | B1 | MESSAGE_TAG(RFIFO0) | EOQ )

};

 

But conversiton results are not much I wait, output on RFIFO0 -> gives in range of 2681 and 4095 (12 bit conversition). I think it can not give 4095 because of voltage difference is at most 3.3 V.

 

Is this test correct to understand the Diff. ADC is just working? If answer is NO, how can I test it easily?

 

 

Not: R2 and R3 is 1K ohm, R1 22K ohm pot.

 

Best regards,

Umit.

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