• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 97 subscribers
  • Views 283 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.

RTC OK to be powered when not configured on TMS320C674X DSP?

M E
Prodigy 40 points

I have measured a significant difference (6x) between the back-up clock current when configured and when not configured or configured improperly.  When not configured, it draws more current and I'm curious if this is an appropriate steady-state condition or should safeguards be built in to prevent continued powering of the RTC circuit when the clock is not configured.

 

Thanks,

  • 0
    TI__Guru 62975 points

    M E,

    The increased current leakage is expected because:

    1. The RTC module is not hooked up to device reset (which is required for the RTC to operate while the rest of the device is powered off) and
    2. Without RTC software configuration (and no hardware reset), the power isolation circuitry in the RTC module may not be enabled on device power up

    The increased leakage should not damage the device, but it is recommended that the module be configured with CTRL_SPLITPOWER set to eliminate the leakage.  Note that this is a tricky bit because it is writeable, but only reads back 0 so read-modify-write updates have the tendancy to clear the bit.

    In Silicon Revision 2 for C674x devices, the bit is internally tied high so that the CTRL_SPLITPOWER bit is always set.  Writes to the bit should not have any affect. 

    -Tommy