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DRV8301LS12kit - TMS570LS1227 control card - Analog input

rathinavel j
Intellectual 645 points

Hi,

I am Trying to use the Ext-IA-FB and Ext-IB-FB pins 19 and 69 of DIM100 for measuring some analog signals.

I removed the R133 and R134 resistance in the DRV kit ( refering schematic drawing RevD of DV8301), and I made the analog outputs to float.

Now I downloded my software which is configured to read  Ext-IA-FB and Ext-IB-FB instead of IA-FB and IB-FB.

by replacing ADCselect group1 with 0x00444000 instead of 0x00240200. I have not done anyother modification in the code.

Now ADC1group 1 is configured for

1.Ext-IA-FB ADC        ( AD1IN14 in TMS570 control card)  

2.VDCBUS                 (AD1IN18 in TMS570 control card)

3. Ext-IB-FB                (AD1IN22 in TMS570 control card)

 

My problem:

Once I give Motor Enable command, 

The TP24 - GND and TP 25 -GND is measuring 1.3 V . ( but i didnt connected any input to that terminal)

Is it possible that a analog output in float will measure some voltage.?

Also when I grounded TP25, Ext-IA-FB is reading zero. but VDCBUS measurement in (Pin11 of DIM100) is also affecting ( that is count in the register of VDCBUS is also varied), but in actual the PVDD supply is stable.

Could you please suggest solution to my problem?

Is there any other configuration I need to do for analog input? or it is problem of something else?

Thanks & Regards

Rathinavel

  • 0
    Intellectual 645 points

    HI,

    Some more input to my question.

    The variation in VDCBUS is only in the controller, but in actual when I measured the voltage at that pin, it is just vary by 4mV when I grounded TP25 and TP24. Similary PVDD supply also stable as I mentioned in the previous post.

    Is there any problem in ADC data readin?. But I checked in the buffer address 0xFF3E0000, it is also reading the same wrong value.

    your help will be very useful as I dont have any other analog input to configure in  my evaluation module DRV8301Ls12.

  • 0 in reply to rathinavel j
    TI__Prodigy 710 points

    Thanks for using the Hercules forum! An engineer has been notified of your issue.