DRV8308EVM: Where is the clock generated by the MSP430?

Peter,

Can you show us a screenshot of exactly which GUI version you are using?

Regards,

-Adam

A screenshot with the About page is attached.

I downloaded the EVM software from the link on the DRV8308EVM Product Page.

DRV8308 EVM Software (Rev. F)

(ZIP, 8857 KB)    12 Sep 2018

The EVM User’s guide section 4.2 Tuning Process, step 3 says

3. Turn on the clock, and start the motor with ENABLE. If the …..

My question is how do I turn on the clock, because I get no clock out of the MSP430.

Regards

Peter

Peter,

Thank you for your post and email. Have you tried switching the Clock dropbox as shown on the Clock Frequency Mode tab:

Also make sure this box is checked on the last tab:

Please also ensure that jumper JP9 is installed and that P5 is uninstalled. This allows the clock signal from the MSP430 to route to the DRV. Measuring at the CLKIN pin of P5, you should see the clock.

Regards,

-Adam

Adam,

Thanks for the reply. I've tried everything you mention. I've also checked there's no short to ground on that line and that the track is continuous from the pin of the MSP430 through the link to the DRV8308. I can see other control lines (DIR and ENABLE) being driven by the MSP430 when I change settings in the GUI. Only explanation is that pin is damaged on the MSP430, which seems unlikely when everything else seems to work, or that there's something else in the GUI that controls it. I'll keep looking.

Regards

Peter

Adam,
Some more information. In the PWM modes tab if I select 'PWM from MSP430' in the Control Mode Select drop-down the PWM signal appears on the CLKIN line, proving that the line is OK, and that the MSP430 can drive it. So it must be something about the GUI not setting up the MSP430 correctly. You asked about versions of the GUI earlier, is there another version I could try? Of course I could drive the CLKIN line from an external frequency generator but I was hoping to avoid that.

Regards

Peter

More information again. If I'm in the PWM modes tab and change between 'PWM from MSP430' and 'PWM from Speed register' I can see that change the contents of the SPDMODE register bits in the All Registers tab. However if I change to the Clock Frequency tab and select either 'CLK from MSP430' or 'CLK from external signal' the SPDMODE register bits never change. If I manually change the SPDMODE register to FREQ it gets changed back to PWM (or speed). It doesn't seem possible to select Frequency. 

I've connected an external signal generator onto CLKIN (removed JP9) but since I can't set the DRV8308 correctly it won't operate correctly. 

I'm pretty convinced something is wrong with my version/installation of the GUI that's not driving the MSP430 correctly.

Regards

Peter

Peter,

Thanks for the info. Have you downloaded the GUI recently? I doubt it changes anything but a newer GUI was released in September. Could you uninstall the current GUI and reinstall it from a fresh download on ti.com?

Regards,

-Adam