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

Part Number: LAUNCHXL-F28069M


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

which was also recommended  in

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



  • 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.


  • 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.


  • 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.