MCF8316AEVM: Problems with the auto read

Linus R.

Part Number: MCF8316AEVM
Other Parts Discussed in Thread: MCF8316A, MCF8315A

Hello,

If I disable both auto read in the GUI I can read all the parameters as well as write new values into the registers. When I activate auto read the motor stops after a few seconds of spinning. The GUI then shows that it is in the MPET KE_MEASURE state. It is not possible to leave this state. In addition, no error messages are displayed. The power supply must be disconnected so that the motor can be rotated again. Now the question is if you have a solution for this problem, and if my board is broken or if I am doing something wrong.

Thanks for the help.

over 2 years ago

0 Hong Khor over 2 years ago

TI__Intellectual 1240 points

Hi Linus,

It looks like you are running into the #8 error described in this FAQ (https://e2e.ti.com/support/motor-drivers-group/motor-drivers/f/motor-drivers-forum/1066777/faq-production-device-information).

Try spinning the motor without activating any "auto read" options, and let me know if there are any other issues.

Best,

Hong

0 Linus R. over 2 years ago in reply to Hong Khor

Prodigy 40 points

Hi Hong,

it works like I said but like you said that's only a workaround. I want to read my registers all the time. what's wrong here why can't I? I have relieved the symptoms but not solved the problem.

Best, Linus

0 Hong Khor over 2 years ago in reply to Linus R.

TI__Intellectual 1240 points

Hi Linus,

According to the FAQ, it is a device firmware issue with the MCF8316A, where constantly reading registers causes device I²C communication to fail. If you wish to read registers all the time, you could use the MCF8315A, a lower-power device which does not have this issue. What is your operating voltage and peak current?

Best,

Hong

0 Linus R. over 2 years ago in reply to Hong Khor

Prodigy 40 points

Hi Hong,

The device is supplied with 13 V. The power supply delivers a maximum of 30 A and the maximum motor current in the Gui is set to 6 A.

Best,

Linus

0 Hong Khor over 2 years ago in reply to Linus R.

TI__Intellectual 1240 points

Hi Linus,

What is the peak output current that the motor itself uses? The MCF8315A (https://www.ti.com/lit/ds/symlink/mcf8315a.pdf) supports a peak output winding current of 4A.

Best,

Hong

0 Linus R. over 2 years ago in reply to Hong Khor

Prodigy 40 points

Hi Hong,

I use the MCF8316A which in my opinion supports a current of 8 A. This current I have not measured so far but since the current from the power supply which goes into the EVM does not exceed 2 A I do not think that the current goes into the motor is much higher.

Best,

Linus

+1 Hong Khor over 2 years ago in reply to Linus R.

TI__Intellectual 1240 points

Hi Linus,

When you say that the current does not exceed 2A, are you talking about peak current or RMS current? If you are talking about peak current, I would recommend the MCF8315A as a better fit, which fixes the I2C issue and still supports up to 4A.

Best,

Hong

0 Andrew Liu over 2 years ago in reply to Linus R.

TI__Mastermind 18981 points

Hi Linus,

Do you still require further assistance on this?
Please help mark the thread as resolved if there are no further questions. Thanks.

Best Regards,
Andrew

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MCF8316AEVM: Problems with the auto read