SOLVED: Thingy fails to enter sleep on BLE adv timeout

NordicSemiconductor / Nordic-Thingy52-FW

Nordic Thingy:52 software development kit. This kit is designed to assist users in developing their own custom firmware for Thingy. Please see http://www.nordicsemi.com/thingy for the latest news and software releases.

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SOLVED: Thingy fails to enter sleep on BLE adv timeout #16

Closed binaryfields closed 6 years ago

binaryfields commented 6 years ago

Upon BLE adv timeout, thingy_ble_evt_handler in main.c calls sleep_mode_enter function. This function in turn will call:

err_code = sd_power_system_off();

The problem is that this will return without putting device into sleep. This is without debugger attached to the device.

Repro steps:

Get FW 2.0.0 from git.
To speed up adv timeout, change thingy_config.h APP_ADV_TIMEOUT_IN_SECONDS from 120 to 15
Flash SD and FW.
Detach debugger.
Reset device.
Upon boot, thingy will enter adv mode with LED set to breathe mode.
Wait 15 or more seconds.

Expected:

Device will enter sleep mode, LED will be off, and device will not be discoverable over bluebooth.

Actual:

Notice that LED will keep blinking blue (as per UI_CONFIG_DEFAULT_DISCONNECTED setting).
Device is discoverable over bluetooth.

binaryfields commented 6 years ago

I changed sleep_mode-enter function to have a delay right after call to sd_power_system_off:

err_code = sd_power_system_off(); nrf_delay_ms(5000); // <--- added

This in turn will cause a pause between reset that happens immediately after call to sd_power_system_off and in turn LED blinking will stop during that period. After the delay, the device resets and LED blinking along with adv starts again.

binaryfields commented 6 years ago

Also please note this behavior is observed in release mode (DEBUG flag in CFLAGS not set).

binaryfields commented 6 years ago

I also commented out low power accelerator configuration to make sure its not interfering with sleep.

In sleep_mode_enter:

// err_code = m_motion_sleep_prepare(true); ... // nrf_gpio_cfg_sense_input(LIS_INT1, NRF_GPIO_PIN_NOPULL, NRF_GPIO_PIN_SENSE_HIGH);

binaryfields commented 6 years ago

Apparently the good old "did you try to power it off and on again" may be the culprit here. I think the issue I was running into was that upon disconnecting debugger, you have to power off and on the device. Resetting the device is not enough.

koffes commented 6 years ago

Nice to see that you found a solution. If you want to know the Thingy debug status, try checking the following flag: DWT->CYCCNT != 0 (Active debug session). There are seven different methods of resetting the nRF52832, and only some resets the device from debug. Consult the nRF52832 Product Specification chapter 18.8 for more information.