CCS/TMS320F28377S: Using encoder with DSP

Milarepa

Part Number: TMS320F28377S
Other Parts Discussed in Thread: C2000WARE, TMDXIDDK379D, CONTROLSUITE

Tool/software: Code Composer Studio

Hi all,

I need to connect a 2000 PPR encoder to my motor. I am using TMS320F28377S DSP. I have not used an encoder before. Are there any sample codes. How to get started.

Kindly let me know.

Thanks

over 5 years ago

0 Ramesh Ramamoorthy over 5 years ago

TI__Mastermind 27240 points

If your encoder is incremental type, then examples are available in C2000ware. If you already installed it, you may see it at

C:\ti\c2000\C2000Ware_2_00_00_03\device_support\f2837xs\examples\cpu1

Look for examples under 'eqep***' folder

For system level examples, you need to install motor control SDK (MCSDK) from TI. If installed, you will find examples at

C:\ti\c2000\C2000Ware_MotorControl_SDK_2_01_00_00\solutions\tmdxiddk379d

There are similar example projects available in controlsuite in the previous bit field type coding style. If you have controlsuite installed, then look at the following

C:\ti\controlSUITE\device_support\F2837xD\v210\F2837xD_examples_Cpu1

For system level old example, refer to the one below for various encoders.

C:\ti\controlSUITE\development_kits\TMDSIDDK_v2.0

If your encoder is incremental quadrature type, then select the encoder type as QEP in the code. Documentation is given the ~Docs folder.

0 Milarepa over 5 years ago in reply to Ramesh Ramamoorthy

Expert 1680 points

Thanks for the suggestions.

I have the enoder pulses which is of +5V and 0V. Can i give these directly to eqep1A?

0 Ramesh Ramamoorthy over 5 years ago in reply to Milarepa

TI__Mastermind 27240 points

No you need to level shift it to 3.3V before feeding to C2K.

0 Milarepa over 5 years ago in reply to Ramesh Ramamoorthy

Expert 1680 points

A potential divider will be fine?

What is c2k?

0 Ramesh Ramamoorthy over 5 years ago in reply to Milarepa

TI__Mastermind 27240 points

I meant C2000.

If it is just a simple experiment with the encoder, you may try with res divider. Since it may be noise prone, buffering it may be better.

0 Milarepa over 5 years ago in reply to Ramesh Ramamoorthy

Expert 1680 points

Thank you Sir. I will try using buffers.

0 Milarepa over 5 years ago in reply to Milarepa

Expert 1680 points

Sir,

This is my encoder out pulses. I can see some ringing at the edges, though there isnt much noise. I am planning to put a 2.2k and 3.3k resistive divider and connect its output to DSP pins for A,B and I signals. What are the High and Low values.

Is this ok.

Thanks for your comments and suggestions.

0 Ramesh Ramamoorthy over 5 years ago in reply to Milarepa

TI__Mastermind 27240 points

Minor ringing at the edges should be ok.If you make the logic high to 3.3V, you should be good.

0 Milarepa over 5 years ago in reply to Ramesh Ramamoorthy

Expert 1680 points

Sir,

"If you make the logic high to 3.3V........." Could you please elaborate on this.

Does it mean that the output voltage at the potential divider should be some 3V correesponding to 5V of encoder output

.But because of the ringing at the edges, the output voltage at the pot divider can be more than 3,3V. WIll that be of any problem?

Thanks

0 Ramesh Ramamoorthy over 5 years ago in reply to Milarepa

TI__Mastermind 27240 points

Yes,

For ringing, it should be ok, otherwise you will find out. Real world signals are not necessarily perfect.

Let us know if the issue is resolved.

0 Milarepa over 5 years ago in reply to Ramesh Ramamoorthy

Expert 1680 points

Ringing voltage peak going above 3,3 V at the output of pot divider....which is going to a DSP pin....Is that fine?

0 Ramesh Ramamoorthy over 5 years ago in reply to Milarepa

TI__Mastermind 27240 points

I hope you had the time to find the answers experimentally. If the issue is resolved, click to close the thread. thanks.

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CCS/TMS320F28377S: Using encoder with DSP