How can I read analog COS and SIN voltages with LAUNCHXL-F28069M?

I am trying to excite and evaluate a resolver with a Launchpad F28069M in combination with the TMDSRSLVR C2000 Resolver to Digital Conversion Kit.

I am targeting the set up / hardware connection described in:

https://de.mathworks.com/help/supportpkg/texasinstrumentsc2000/ug/hardware-connections-c2000.html

I am facing the following problem: I want to read in the SIN and COS voltages using the ADC. Apparently, the voltages received are in the range of +/- 0.5V while the ADC voltage range is 0-3V. Hence, the digital signals are cut off at "0" so that proper angle/speed calculation is not possible. The example simulink model shown in

https://de.mathworks.com/help/mcb/gs/monitoring-resolver-using-serial-communication.html?searchHighlight=monitor%20resolver&s_tid=srchtitle_monitor%20resolver_1

implies that the resolver evaluation is possible. Can anyone help me, how proper COS/SIN reading can be achieved?

Many thanks

Nils

Answer 1

[Mukul Choudhury]

Hi,

The example mentioned by you uses the TI TMDSRSLVR - Resolver EVM kit. This resolver uses a level shifter and a gain amplifier using Texas Instruments TLV2772 to fit the reolver signals within the ADC range.

Due to the level shifter, the reolver signals which are fed to the ADC are in the ramge of 0- 3.3 V.

Please refer to the following lik for more details:

https://www.ti.com/tool/TMDSRSLVR

Hope this helps.

Regards,

Mukul

[Johan Lecoutere]

Would it be possible to use one ADC to measure the positive part and another for the negative part of the signal? Then combine the two?