MCF8316AEVM: BRAKE_ALIGN not possible with GUI?

Hi

We are out of office today. 

We will respond to this by tomorrow. 

Thanks and Best Regards 

Venkatadri S 

Hi Joe Carlson,

Those controls which are made reserved or locked are only for test purpose and not recommended for regular operation.

We will be introducing these features in next revisions.

Thanks and Best Regards 

Venkatadri S 

Hi Venkatadri,

Do you have an estimate for when this feature would be available?

Hi Joe Carlson,

We will update you soon about the release plan.

Thanks and Best Regards 

Venkatadri S 

Am I still able to use PN: MCF8316A with a sensored motor to get homing capabilities? Does it matter what type of sensor the motor has? I have one with an absolute encoder that communicates over an SSI bus (not a hall sensor motor).

Based on the datasheet I was under the impression these functions were already implemented. Is there a part that DOES have this implemented?

Hi Joe,

Venkatadri is out today. Please expect a response early next week.

Regards,

Joshua

Hi Joe Carlson,

There some errata in MCF8316A, please check this link (+) [FAQ] Production device information - Motor drivers forum - Motor drivers - TI E2E support forums

This device has working homing capability, we can use this device without any problem.

Please refer to the errata and take care of conditions.

Thanks and Best Regards

Venkatadri S

In the thread above you said the MCF8316A does not have alignment braking capabilities yet. In the datasheet it has a section detailing how to use the align braking feature (which I would like to use). 

Is there a way to use the alignment braking feature at this time with MCF8316A?

I'm guessing that "homing capability" is different than "brake alignment" based on our discussion. Can you please tell me whether I can put the rotor in a known position before cutting the motor off?

I appreciate your continued support Venkatadri and team!

I don't need holding torque when the rotor is in the aligned braking position. I just need the rotor to stop in the set position obviously with some tolerance.

Hi Joe Carlson,

I am out of office, I will respond by tomorrow.

Thanks and Best Regards

Venkatadri S

Hello,

Looking to get a response on this. Seems like if it is in the datasheet, then it should be a working feature.

Hi Joe Carlson,

As mentioned earlier the ALIGN BRAKE is used with force condition (debug).

We provided as feature but the main use case of holding the rotor forever is not possible.

There is MTR_STOP_BRK_TIME , when we stop at an angle, device keeps the angle until the timeout (configurable up to 14 seconds) and then releases to Hiz.

We provide this a knobs for tuning purpose and hence removed it from STOP mode and also Fault modes.

Thanks and Best Regards

Venkatadri S

How do I control the angle at which the rotor stops using MTR_STOP_BRK_TIME?

I still think there should be an asterisks or something by the align braking paragraph in the datasheet saying that it is for debug only - not normal use. I had no way of knowing prior to purchase. It does sound like you can brake at a specific angle though which is what I need, just has a different name through MTR_STOP_BRK_TIME.

I would think the alignment angle would be set using ALIGN_BRAKE_ANGLE_SEL register but it is locked in the GUI no matter what brake mode I am in.

I need a list of register settings to change so that the motor stops at the same position every time it spins down. I don't need it to have holding torque (it can be Hi-Z) once stopped at the home position, but it has to go to the home position.

Thanks!

Hi Joe Carlson,

For debug purpose, we can use following method

1. Select start up mode as ALIGN :  MOTOR_STARTUP1[MTR_STARTUP] = ALIGN

2. Algorithm control registers ALGO_DEBUG1[FORCE_ALIGN_EN] = Enable Force Align State; This enabled force align and up on motor start command, device starts with ALIGN, completed ALIGN state for the period programmed through MTR_STOP_BRK_TIME and exits

3. Align angle can be selected from following locations

3.1 If we select ALGO_DEBUG1 [FORCE_ALIGN_ANGLE_SRC_SEL] =  ALIGN_ANGLE , then MOTOR_STARTP2 [ ALIGN_ANGLE] = 0,10, 20, ...350 one of the selected value is applied

3.2 If we select ALGO_DEBUG1 [FORCE_ALIGN_ANGLE_SRC_SEL] = FORCED_ALIGN_ANGLE, then ALGO_CTRL1 [FORCED_ALIGN_ANGLE] = Write any value 0 to 360 which will be applied

We will be updating notes in the next revision data sheets.

Thanks and Best Regards

Venkatadri S

Thanks Venkatadri!

You made it sound like a specific (selectable) angle can be used as an input to the MTR_STOP_BRK_TIME register. Is it possible to have the rotor hold a known / selectable position during braking for a short time (1s) before putting the rotor in Hi-Z? Or is the motor simply held at whatever rotor angle happens to be current for a known / selectable time (up to 14s) before releasing to Hi-Z?

Hi Joe Carlson,

We can set for 1 second, you can see list of 16 values in the 1s option also available.

Thanks and Best Regards

Venkatadri S

Great! Can you please walk me through how to do that without using the debug registers you shared earlier?

Hi Joe Carlson,

I will reply to you by week end.

Thanks and Best Regards

Venkatadri S

Hi, can you please provide an update on this?

Hi Joe,

Venkatadri is currently on Holiday. Please anticipate a response sometime next week.

Regards,

Joshua