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F28035 Controlcard SW3 settings

Scott Kerstein
Expert 1395 points

According to the 28035 Controlcard Info Sheet:

Position 1 controls VREF-HI, the value that the ratiometric ADC will convert as

the maximum 12-bit value, 0x0FFF. In the downward position, VREF-HI will be

connected to 3.3V. In the upward position, VREF-HI will be connected to pin 66

of the DIMM100-socket. This would allow a connecting board to control the

ADC-VREFHI value.

 

Position 2 controls VREF-LO, the value that the ratiometric ADC will convert as

the minimum 12-bit value, 0x0000. In the downward position, VREF-LO will be

connected to 0V. In the upward position, VREF-LO will be connected to pin 16 of

the DIMM100-socket. This would allow a connecting board to control the ADCVREFLO

value.

Q1: What is the correct position for using this card in a BLDC sensored motor control application?

Q2: The SW3 switch has "OC" marked on the left and Pin Dot on the right, what defines Position 1 and 2 settings?

 

  • 0
    TI__Guru 57255 points

    Scott,

    By default, the ADC references are based on internal bandgap references and not based on VREF-HI and VREF-LO.  To use VREF-HI or VREF-LO, the bit ADCREFSEL in the ADCCTL1 register will need to be changed.  Using external references is only necessary for applications in which ADC measurements need to be extremely accurate.

    Q1: What is the correct position for using this card in a BLDC sensored motor control application?
    A1:  The correct position will depend on your application.  For most BLDC projects, I would assume that using the internal bandgap reference is adequate and so SW3's configuration will not matter.

    Q2: The SW3 switch has "OC" marked on the left and Pin Dot on the right, what defines Position 1 and 2 settings?
    A2:  The dot does.  For extra clarity, if you orient the controlCARD such that the controlCARD DIMM connectors are down, position 1 will be the leftmost switch on SW3 and position 2 will be the one to the right.


    Thank you,
    Brett