MSPM0G5187: How to use low power mode while using USB feature?

Ryan KIM

Part Number: MSPM0G5187

Hello team,

The code style of USB feature device MSPM0G5187 is different from our original example.

USB function is running under while loop.

And there is no lower power mode instruction.

Is it impossible to use low power mode in USB function? to keep USB communication timing with USB Host?

Or, please share how to adopt low power mode while using USB function(Host or Device).

Thanks

0 Gary Gao 2 months ago

Hi Kim,

It seems the USB can just running at SLEEP0 that the high speed clock still alive to make the USB working.

0 Ryan KIM 2 months ago in reply to Gary Gao

Hi Gary,

USB peripheral can run under SLEEP0 mode.

But I'm curious how to apply SLEEP0 mode in our example code.

Our USB example code structure is running under while(1) loop. And I can't find USB peripheral interrupt.

So, we can't determine when to wake up.

How can we use SLEEP0 low power mode while using USB function?

Use Timer(<1ms, USB 2.0 FS) interrupt as a wake up trigger is just hit me... Is that a good way?

+1 Gary Gao 2 months ago in reply to Ryan KIM

Ryan KIM said:
And I can't find USB peripheral interrupt.

It do have interrupt USBFS0_IRQHandler.

You can try to put the sleep in the while loop as below

0 Ryan KIM 2 months ago in reply to Gary Gao

Thanks Gary,

Let me share more details that I thought.

1. USB 2.0 FS's communication period is 1ms -> Use Systick to keep this period

Every 1ms, Systick generates interrupt. So, the code can exit Low power mode(__WFI();)

2. Due to above reason, Systick should run with 80MHz frequency. -> Only run in RUN0, SLEEP0 mode.

If user use SLEEP1 low power mode -> interrupt period is changed.

0 Gary Gao 2 months ago in reply to Ryan KIM

Hi Ryan, thank for your details information, so it works now, right?

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