S32K344 – Quadrature Encoder Example using LCU + eMIOS (RTD)

[gayancho]

I am using S32K344 with PlatformSDK_S32K3 (RTD) and would like to implement a quadrature rotary encoder using LCU, TRGMUX, eMIOS edge counter.I could not find a complete RTD example project demonstrating full quadrature decoding (A/B phase, direction and position calculation).Could you please share a reference example project or application note compatible with RTD?

[VaneB · Accepted solution]

Hi @gayancho 

Please refer to the AN13767: 3-phase Sensorless PMSM Motor Control Kit with S32K344 using RTD Low Level API Application Note, as well as AN13884: 3-phase Sensorless PMSM Motor Control Kit with S32K344 using RTD AUTOSAR API Application Note. These documents may serve as useful references for your application.

BR, VaneB

[gayancho]

Hi @VaneB ,

I have a question regarding scalability.

From the documentation, it appears that the quadrature decoding method using LCU + eMIOS relies on LCU LUT logic resources, which seem limited.

Could you please clarify:

1. How many quadrature encoders can realistically be implemented using LCU + eMIOS on the S32K344?

2. Is the number limited by the available LCU LUT channels?

3. If LUT resources are limited, does this restrict the number of encoders that can be decoded using this hardware method?

4. Is there any recommended method or workaround to support up to 7 encoder channels on this device?

I want to understand whether scaling to multiple encoders is feasible or if an alternative approach should be considered.

[VaneB]

Hi @gayancho 

Yes, the number of supported encoders will be limited by the LCU. Each LCU contains only three Logic Cells (LCs), and every LC provides four inputs and four outputs. Since each encoder requires its own dedicated LC, the maximum number of encoders you can connect is six. However, this number may be lower if other parts of your application also require LC resources.

[gayancho]

Also, could you confirm which eMIOS channel types are recommended for this use case?
Is it correct to use Type X or Type G channels for pulse counting?