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Original question:

LAUNCHXL-F28379D: How to connect with motor resolver signals

LAUNCHXL-F28069M: How to connect Resolver with Launchpad and TMDSRSLVR C2000 Resolver Kit

Nils Trochelmann
Prodigy 20 points
Part Number: LAUNCHXL-F28069M

Hello,

I am trying to connect a resolver to a Launchpad 28069M using a "TMDSRSLVR C2000 Resolver to Digital Conversion Kit". I followed the hardware connection proposed by Mathworks 

de.mathworks.com/.../hardware-connections-c2000.html

which was also recommended  in  

https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/1094839/launchxl-f28379d-how-to-connect-with-motor-resolver-signals

I am able to generate the exciation using ePWM via GPIO2 and to read in the COS/SIN feedback voltages using ADCIN1A/B. Though, I am facing the problem that the SIN/COS voltages are in the range of +/-0.5V (1Vpp). As the Launchpad ADC's input voltage range is 0-3V the digital signals are equal to zero when the voltages are negative. Can somebody help me out here?

The alternative would be to insert a CPU (F28335) in the resolver board, let it do the resolver evaluation, and send the result to the launchpad via SPI. I am failing to implement this solution as well, as there is no documentation on the SPI signal sent by the resolver evaluation software so I do not know how to configure the receive block in Simulink. 

Can anyone support me in either one of these approaches?

Many thanks in advance

Nils

 

  • 0
    TI__Expert 5985 points

    Hi Nils,

    For the Sin/Cos feedback issue, can you try to check if 5V and 3.3V supply is in place on the board? The EXC amplifier is running on 15V, while the feedback signal chain runs on 3.3V supply. After confirming the power, you can also check if 1.65V bias voltage is available.

    Han

  • 0 in reply to Han Zhang6
    Prodigy 20 points

    Hello Han,

    thanks for your reply. I will check as you have suggested.

    In advance, what would I do in case: 

    [a] I cannot confirm power,

    [b] bias voltage is not available?

    Thanks for your help.

    Nils

  • 0 in reply to Nils Trochelmann
    TI__Expert 5985 points

    Hi Nils,

    If you do not see 5V power, try to change position of the input power switch, which select between external feed 5V from vs. the 5V generated from 15V on board.

    If the 5V and 3.3V is present on the board and you still not seeing the 1.65V bias voltage and proper amplification of the signals, mostly likely you have a faulty board and need replace or repair.

    Han