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Demo AduCM36x with ADuCM362 questions

Question asked by Bill-S on Aug 3, 2018
Latest reply on Aug 8, 2018 by Bill-S

Need help understanding some demo program settings.  We are using the Keil MDK uVision IDE with a ADuCM362 device.  The Blinky example in the ADuCM36x 1.0.3 Pack works fine but we are having some issues with imported examples from the ADuCM360 side.  We updated the IDE target options to use the ADuCM362 device and modified the demo code to point to ADuCM362.h instead of ADuCM360.h.  We also updated the debugger to select the J-Linker with SWD instead of the U-Linker used in the ADuCM360.  Now here are some questions.  The ADC_Read demo reads a 1.6V battery as 0.6V.  I was expecting and overrange or 1.2V value from the code.  If I change the reference value in the demo code from 1.2 to 3.232 we get very precise readings of the test reference voltage that matches the values we get with an external precision meter.  Why did the demo code not use the reference voltage setting?  I think it might be using the J-Link feed power voltage instead?

 

Next question - we have tried the RTD_Demo program.  The program says the reference current is set at 100 microamps but that gives a resistance that is nearly half of expected.  We changed the current to 200 microamps output and the IEcur = fAin1V/5600 to  IEcur = fAin1/6000 and resistance calculates to near expected values.  The 1.2V reference value measured at 1.192V so it was as expected.   Using a high precision picoammeter across the Ain1/Ain0 where the RTD would be connected we get a precise 100 microamps which is half of what we expected.   Can anybody explain why the ADuCM362 is different?  I would also like to know where the 5600 value came from in the demo code.  It is used in most of the temperature measurement examples.  I could not find it explained in the chip hardware reference.

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