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MCF8329A: Sleep related issues

chuanlin zhou
Prodigy 50 points
Part Number: MCF8329A

Tool/software:

Hi，

Is there a recommended sleep process for MCF8329A? Is it feasible to directly give SPEED/WAKE low level?

At present, I am using BRAKE and DRVOFF to high level and then SPEED/WAKE to low level, but this will result in the inability to enter Sleep mode 100%,

Most likely to enter standby mode

  • 0
    Prodigy 50 points

    To add, if the motor is not connected, sleep is normal and will enter Sleep mode every time, approximately 2uA.

    But when connected to the motor, the current after sleep is 24mA, suspected to be entering Standby mode.

  • +1 in reply to chuanlin zhou
    TI__Genius 9210 points

    Hi Chuanlin,

    Please refer to datasheet Table 7-6 for all Sleep entry conditions:

    Could you please help confirm:

    • [DEV_MODE] is set to 1b
    • What is [SPEED_MODE] set to?
    • If [SPEED_MODE] = 0b (analog mode), what is [DAC_SOX_ANA_CONFIG] set to?
      • if [DAC_SOX_ANA_CONFIG] = 2h, refer to 2nd row in Table 7-6
      • else refer to 1st row in Table 7-6

    Regards,
    Eric C.

  • 0 in reply to Eric Chen
    Prodigy 50 points

    Hi Eric,

    DEV_MODE = 1

    SPEED_MODE = 00b

    DAC_SOX_ANA_CONFIG = 0

    The current phenomenon is occasional standby.  Of course, it could also be caused by other reasons.

    At present, the software enters the sleep process as follows:,

    Send I2C command SLEEP_ENTRY_TIME = 1

    BRAKE->HIGH

    DRVOFF->HIGH

    Send I2C command, DEV-PODE=1

    Send I2C command, ACTIVE.BRAKE-IN=1

    SPEED/WAKE = 0

    Delay of 300us

    Excuse me, is there a problem with the above process?

  • +1 in reply to chuanlin zhou
    TI__Genius 9210 points

    Hi Chuanlin,

    I don't see a major problem with the process above. Though, I'm not certain what's the purpose for setting ACTIVE_BRAKE_EN = 1 before entering sleep. Are you intending to use this to stop the motor?

    Is DEV_MODE written as 1 in the device EEPROM?

    When the device enters sleep, the values in the device shadow registers are lost, and when the device wakes up, it'll reload the register settings from its EEPROM register memory, including the DEV_MODE bit.

    If DEV_MODE is not 1 in the EEPROM, then you'd need to set DEV_MODE = 1 every time before entering sleep.

    If you have a MCU controlling when to put the device to sleep, here's an example of how I would utilize DEV_MODE to enter sleep:

    • Keep DEV_MODE = 0 in EEPROM.
    • Device will enter Standby by default when SPEED/WAKE pin < Ven_sb
    • When MCU needs to put MCF8329 into sleep:
      • Set SPEED/WAKE pin to 0 (this will stop the motor based on MTR_STOP option), device will enter standby
      • Set DEV_MODE = 1 to put device into sleep

    Regards,
    Eric C.

  • 0 in reply to Eric Chen
    Prodigy 50 points

    Thank you very much! 

  • 0 in reply to chuanlin zhou
    TI__Genius 9210 points

    Hi Chuanlin,

    You're very welcome. Please let me know if you still have issues with sleep entry.

    Regards,
    Eric C.