controlling 4 brushed DC motor with one DSP (TI TMS320F2812) 1

[johnwzy]

I need to control 4 brushed DC motor with one single DSP (TMS320F2812). In addition to PWM generation, the DSP needs to process the feedback signals from 4 quadrature encoders.

The problem is that one TMS320F2812 can only handle up to 2 motor/encoder pairs. I don't want to use a multi-processor configuration.

Any suggestions on the selection of interface chips?

 

[itsmoked]

Look here.. They aren't cheap but they are great parts.

http://www.pmdcorp.com/

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[itsmoked]

You can use one of PDM's chips to control all 4 motors. Then use a lower end DSP or be able to do more tricks. I wouldn't do two in the DSP and two some other way unless I wanted to spend about three times the time needed to design the job.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[johnwzy]

Thank you, Keith. Yes, PMD has several chips that can handle up to 4 axis per chip. But they seem to be overkills for my application. I just need some PWM generator which takes commands from the host DSP and provides PWM to H-bridges. Also, I need counters which can handle quadrature encoder signals and send results to the DSP.

 

[cswilson]

Check out Avago's (formerly Agilent, formerly HP) encoder interface chips -- the HCTL-20xx ICs. They incorporate quadrature decode, counter, latch, and processor interface. I believe the newer ones handle two encoders in one IC.

 

[johnwzy]

Thanks a lot, cswilson. This encoder interface chip is what I needed. But I still need to find the chip for PWM generation.

 

[johnwzy]

Just found MsKennedy MSK4200 H-bridge w/ internal PWM generation. I will probably go with a DSP->D/A Converter->H-bridge w/ PWM-> brushed DC motor configuration.

 

[itsmoked]

If this is for production... watch out using odd chips. You could easily be regreting it.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com