Selecting external 32KHz LPO in source code.

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WaSu_1697556
Level 3
Level 3
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Hi,

I hope to get answers to the following two questions.


I enabled external 32KHz LPO on TAG03 board by connecting it to BCM20737.


I have the following function call in my app but the app seems to work fine with or without it.  Is the call absolutely necessary?

bleapputils_changeLPOSource(LPO_32KHZ_OSC, FALSE, 250);

Also, my app has a part where enters deep sleep.

The part has the following statement before calling devlpm_enterLowPowerMode().  Is this assignment absolutely necessary?

devLpmConfig.wakeFromHidoffRefClk = HID_OFF_TIMED_WAKE_CLK_SRC_32KHZ;

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3 Replies
Anonymous
Not applicable

Hello Wataru,

Have you seen this post:

Re: how to config RTC use external 32.768?

Thanks

JT

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Hello j.t,

Thank you for the post.

However, I don't use RTC.

Do I still have to explicitly select ext 32KHz LPO in the source code?

BR,

Wataru Sugimoto

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Anonymous
Not applicable

Helloi Wataru,

Please loot at the rtc_sample code in the SDK:

// If we need to use the external 32K, then configure the reference

rtcConfig.oscillatorFrequencykHz = RTC_REF_CLOCK_SRC_32KHZ;

 

// Since the 32K external LPO is connected tp P10, P11, P12, P26 and P27,

// input and putput disable all 5 GPIOs.

gpio_configurePin(0, 10, GPIO_INPUT_DISABLE, 0);

gpio_configurePin(0, 11, GPIO_INPUT_DISABLE, 0);

gpio_configurePin(0, 12, GPIO_INPUT_DISABLE, 0);

gpio_configurePin(1, 10, GPIO_INPUT_DISABLE, 0);

gpio_configurePin(1, 11, GPIO_INPUT_DISABLE, 0);

 

   // Initialize the RTC.

Thanks

JT

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