NRF_ERROR_BUSY returned, re-starting BLE beacon advertising

[Brian]

Hey guys,

Working with the simple be_app_beacon example on nRF51. I’d like to be able to stop and start advertising. But after stopping advertising, I’m unable to start it again. On the call to start advertising I’m getting an err_code of NRF_ERROR_BUSY.

I’m guessing the structure of the code here isn’t allowing the BLE stack to process the previous call to stop the advertising, before I try to start it again. Is there a really simple, nice way to fix this? It's just a basic NON connectable beacon. See simplified code below in my main loop.

Sorry for the newb question. Hoping to keep the code really clean. Much appreciated.

Thanks, Brian

main() {

ble_stack_init();

adv_beacon_init();

advertising_start();

delay_flag = FALSE;

app_timer_start(…); // sets delay_flag to FALSE after 1 second

while(delay_flag) power_manage();

sd_ble_gap_adv_stop();

//do stuff here… not BLE related

err_code = sd_ble_gap_adv_start(); //!!! here’s where err_code == NRF_ERROR_BUSY

//do more stuff, then call sd_power_system_off();

}

[Petter Myhre]

I'm not sure what is causing this. Would it be possible for you to upload your complete project? Or a project that produces the error? What SoftDevice and SDK version are you using?

[Brian]

Hi Petter,

Thanks for the response. I figured something out:

The settings causing this behavior are:

#define APP_CFG_NON_CONN_ADV_TIMEOUT  1
#define NON_CONNECTABLE_ADV_INTERVAL    MSEC_TO_UNITS(1000, UNIT_0_625_MS) 

If I change to:

#define APP_CFG_NON_CONN_ADV_TIMEOUT  0
#define NON_CONNECTABLE_ADV_INTERVAL    MSEC_TO_UNITS(1000, UNIT_0_625_MS) 

Then no problem. Why is this? I'm trying to just send one advertisement per second, but be able to start and stop. Should these settings also send just one advertisement per sec?

Thanks, Brian

[Petter Myhre]

#define APP_CFG_NON_CONN_ADV_TIMEOUT  1
#define NON_CONNECTABLE_ADV_INTERVAL    MSEC_TO_UNITS(1000, UNIT_0_625_MS)

This will send one advertisement per second for 1 second.

#define APP_CFG_NON_CONN_ADV_TIMEOUT  0
#define NON_CONNECTABLE_ADV_INTERVAL    MSEC_TO_UNITS(1000, UNIT_0_625_MS)

This will send one advertisement per second forever, or until you call sd_ble_gap_adv_stop().

If you always want to stop the advertisements manually you can set the timeout to 0.

[Petter Myhre]

What error code do you get with sd_ble_gap_adv_stop()?

[Brian]

Yup. Got that. What I'm finding in SDK9-2 is that if the timeout is 1 second. And I wait more than 1 second after starting advertising, then trying to restart advertising after the timeout period I get the NRF_BUSY error.

With timeout of 1 second, and a delay of only 500ms, let's say, then stoping and starting works ok. Seems strange... but no big deal. Now I'm just setting the timeout to 0, and manually starting and stopping and it's working ok.