TM4C129x hibernation wake pin

Benson Lo

Hello

In the document spma056, System Design Guidelines for the TM4C129x Family of Tiva™ C Series Microcontrollers, Section 4.15

"If the WAKE pin is not used, it should be connected to system ground"

In my custom board, PK[4-7] are configured as hibernation wake up sources and the WAKE pin is connected to Gnd as suggested by the design guide. But I found my board wake up again and again by the wake up pin.

My code setting the wake up source seems doesn't work:

HibernateWakeSet(HIBERNATE_WAKE_GPIO | HIBERNATE_WAKE_RESET);

I need some help to disable the wake pin.

Thanks,

Benson

over 10 years ago

0 Amit Ashara over 10 years ago

TI__Guru**** 244440 points

Hello Benson,

Make sure that the PINWEN bit in the Hibernate Control regisyet is not set.

Regards
Amit

0 Benson Lo over 10 years ago in reply to Amit Ashara

Intellectual 740 points

Hi Amit,

#define HIBERNATE_WAKE_PIN 0x00000010
#define HIBERNATE_WAKE_GPIO 0x00000010
#define HIBERNATE_WAKE_RESET 0x00100010

HibernateWakeSet(HIBERNATE_WAKE_GPIO);

Even I just set the GPIO wake pad, the PINWEN will be set in the above call. Should I call this function or else?

Thanks,
Benson

0 Amit Ashara over 10 years ago in reply to Benson Lo

TI__Guru**** 244440 points

Hello Benson,

I think that the WAKE pin must be tied high.

Regards
Amit

0 Benson Lo over 10 years ago in reply to Amit Ashara

Intellectual 740 points

Hi Amit,

In the document spma056, System Design Guidelines for the TM4C129x Family of Tiva™ C Series Microcontrollers, Section 4.15

"If the WAKE pin is not used, it should be connected to system ground"

So the document contains error and needs to be updated in the next revision.

If all the Wake Pin, GPIO Wake Pad and Reset Pin are not used, it can be connected to Gnd. Otherwise, have to be tied high.

Thanks,

Benson

0 cb1 over 10 years ago in reply to Benson Lo

Guru 47900 points

Benson Lo said:
If all the Wake Pin, GPIO Wake Pad and Reset Pin are not used, it can be connected to Gnd.

Tieing "Reset" to ground may be appropriate when seeking to "disable" the MCU (that fate befalls those MCUs serving as ICDI) but such proves very much a minority, "Use Case."

As you go on to state - Reset (usually) is pulled up (not tied) and bypassed to ground via a small cap for Reset stability...

0 Amit Ashara over 10 years ago in reply to Benson Lo

TI__Guru**** 244440 points

Hello Benson

As cb1 mentioned, Reset Pin must be tied high. Similarly the GPIO Wake Pad need not be tied as the feature is controlled from the HIBIO register, it is the Wake Pin which must be tied high and it could be a documentation error.

Regards
Amit

0 cb1 over 10 years ago in reply to Amit Ashara

Guru 47900 points

Word usage alert! "Tied high" often implies a direct connection to VDD. Pulled up (as stated) is far more preferable (thus customary) as it allows the inevitable "switch of Reset to ground" with less "fire-works!" (you'll "tie" Reset high just once - of that we're sure!)

0 Amit Ashara over 10 years ago in reply to cb1

TI__Guru**** 244440 points

Hello cb1,

Yes, I stand corrected: "Pulled up" and not "Tied High"

Regards
Amit

0 cb1 over 10 years ago in reply to Amit Ashara

Guru 47900 points

Never a "correction" - just fine-tuning - enabled by the 1:100 (Robert/cb1) participation as compared to yours...

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TM4C129x hibernation wake pin