• State TI Thinks Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 1 answer
  • Subscribers 30 subscribers
  • Views 513 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DRV8829EVM: Regarding setting for decay mode.

Kengo.Y
Guru 11255 points
Part Number: DRV8829EVM
Other Parts Discussed in Thread: DRV8829

Hi team.

I'd like to use DRV8829EVM.

I do not know where to set the decay mode in GUI.

In the GUI, we can choice decay mode in different places(Control Signals and Stepper Control).

Could you tell me about the difference?

Sincerely.

Kengo.

  • 0
    TI__Guru** 114905 points
    Hi Kengo,

    In most cases the The PHASE A and PHASE B Control Signals are not required. The control signals allow the user to control the pins of the DRV8829 directly. This can be useful to evaluate the effect of the decay modes when the motor is stopped.

    Please refer to section 4.4.3 for information about the area highlighted in red ("Slow/Fast Decay" and "Mixed Decay").

    When microstepping, the decay settings in the highlighted ares allows the user to observe the difference between slow/fast decay and mixed decay.

    When using slow/fast decay, the mcu sets the decay mode to slow in Quadrants 1 and 3 and to fast in Quadrants 2 and 4 as shown in Figure 9.
  • 0 in reply to Rick Duncan
    Guru 11255 points

    Hi Rick.

    Thank you for your reply.

    I'd like to know more some detail.

    Could you give me your advice ?

    Q1. Is the Decay setting of Control Signals the same as the Decay pin (# 19) setting?

    Q2. If Q1 is so, I can not understand why there is  the Decay setting of Control Signals.

           I think there is only one Decay pin.

    Q3. Where can we observe the Decay mode as your comment (to observe the difference between slow/fast decay and mixed decay)?

    Sincerely.
    Kengo.

  • 0 in reply to Kengo.Y
    TI__Guru** 114905 points
    Hi Kengo,

    Q1. Is the Decay setting of Control Signals the same as the Decay pin (# 19) setting?

    >>> Yes, it is. But there is one per DRV8829.

    Q2. If Q1 is so, I can not understand why there is the Decay setting of Control Signals.

    I think there is only one Decay pin.

    >>> There is one Decay pin per device. There are two devices on the EVM. The Decay setting in the PHASE A box controls pin 19 of one DRV8829 and the Decay setting in the PHASE B box controls pin 19 of the second DRV8829.

    Q3. Where can we observe the Decay mode as your comment (to observe the difference between slow/fast decay and mixed decay)?

    >>> As the stepper motor demo is operated, the Decay pins of both DRV8829 are controlled by the mcu based on the decay setting. The decay mode can be observed in two places.

    >>> First, the J3 and J5 headers have the Decay pin available to monitor. These will change from slow to fast if slow/fast is selected.
    >>> Second, the effect of slow/fast can be observed as the current through the stepper changes from the most positive or most negative back toward 0 current. This can be seen by monitoring the current or the output voltages.
  • 0 in reply to Rick Duncan
    Guru 11255 points
    Hi Rick.

    Thank you so much.
    I understood.

    Could you give me little more advice about GUI control.

    1. Which one('Start Steps' or 'Move Steps' or both) does it use the decay mode that is set on Stepper Control Screen.

    2. When does it use the decay mode that is set on Control Signals.

    Sincerely.
    Kengo.
  • 0 in reply to Kengo.Y
    TI__Guru** 114905 points
    Hi Kengo,

    1. Which one('Start Steps' or 'Move Steps' or both) does it use the decay mode that is set on Stepper Control Screen.

    >>> Both.

    2. When does it use the decay mode that is set on Control Signals.

    >>> Decay Mode of PHASE X Control signals is used when the microstepping demo is stopped.
    >>> The PHASE X Control signals can be used to evaluate driving a one or two brushed DC motors. When operating a brushed DC motor all the PHASE X control and Current Control (VREF) Phase X control are available.