• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 97 subscribers
  • Views 617 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.

Static Power-Down Support on C674x megamodule

Naoki Kawada
Guru 19890 points
Other Parts Discussed in Thread: OMAPL138, SYSBIOS

Hi,

One of my customers is considering to use Static Power-Down (C674x megamodule power donw) on C674x/DA810 device.

http://www.ti.com/lit/ug/sprufk5a/sprufk5a.pdf
9.2.5 C674x Megamodule Power-Down

This UG says that we can put megamodule into static power-down with the following sequence:

1. Enable power-down by setting the MEGPD field to 1 in the PDCCMD register.
2. Enable the CPU interrupt(s) that you want to wake-up the C674x megamodule. Disable all other interrupts.
3. Execute the IDLE instruction.

Can I understand there is no specific requirement for interrupt event ID to awake megamodule ?
My customer is assuming, for example, signaling interrupt from the host device via GPIO can be used for this purpose.

Also, I briefly checked the errata, and I did not see any problems about static power-down. 
So, I believe static power-down could be safely used on C674x/DA810 device, but if you have
any experience to ship the device to the market supporting static power-down, it is very helpful for me
to know that because I could aggressively promote the use of static power-down to my customer.

Best Regards,
Kawada 

 

  • 0
    TI__Guru* 83985 points

    Hello Kawada-san

    Your understanding is essentially correct, you should be able to use any interrupt routed to the megamodule , as a wake up source to get out of the idle mode, as long as that interrupt was enabled and ISR constructed, prior to going to DSP IDLE mode.

    You might find the following link with the BIOS PWRM module useful reference for c674x/OMAPL1x sleep modes

    http://processors.wiki.ti.com/index.php/Power_Module_for_C6748_and_OMAP-L138

    The static power down mode you are referring to is the DSP_SLEEP mode

    Regards

    Mukul

  • 0 in reply to Mukul Bhatnagar
    Guru 19890 points

    Hello Mukul,

    Thank you for your response.
    I understood your points. Actually my customer is using DA810 (c6747). So, Power module in SYS/BIOS can't be used because it is for OMAPL138(c6748).
    But the information of Power module is very helpful for me. Thanks.
    I dug into the Power code in bios_6_35_01_29\packages\ti\sysbios\family\c674\Power.c and I actually found the implementation of "IDLE" instruction with GIE=1 (enabling global interrupt). The same thing should applicable for DA810(c6747). And the wake-up operation should be accomplished with IER=1 (enabling specific interrupt) via Hwi_enableInterupt API or something.

    Best Regards,
    Kawada 

  • 0 in reply to Naoki Kawada
    TI__Guru* 83985 points

    Good to hear that it helps. Yes you should be able to use the source code provided for OMAPL138/C6748 , for implementing this on another C674x based core , in this case OMAPL137/C6747x/DA81x.