Error while configuring cccd metadata, in ble-characteristics-a-beginners-tutorial

[Geoffroy]

I'm using nRF52840 with SDK15.0.0

Following this tutorial : https://devzone.nordicsemi.com/tutorials/b/bluetooth-low-energy/posts/ble-characteristics-a-beginners-tutorial

AT STEP 2.H my module is Advertising i can connect and then see the service and its characteristics write and read with nRF connect app.

Then at  next  step :STEP 3.A, i add : 

		BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.read_perm);
		BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.write_perm);
		cccd_md.vloc                = BLE_GATTS_VLOC_STACK;
		char_md.p_cccd_md           = &cccd_md;
		char_md.char_props.notify   = 1;

Here is problem : there is err_code 0x07 in return from sd_ble_gatts_characteristic_add, and no more advertising.

if i comment APP_ERROR_CHECK where err_code = 0x07, i can see my module advertising but i don't see the service and its characteritics

I tryed to use solutions file, but i get same problem...

[awneil]

Continued from previous thread:

https://devzone.nordicsemi.com/f/nordic-q-a/46981/characteristic-tutorial-error-when-adding-a-characteristic-to-a-service/186578#186578

[Geoffroy]

i just checked values : 

		SEGGER_RTT_printf(0, "read_perm : 0x%#02x\n", char_md.p_cccd_md->read_perm);
		SEGGER_RTT_printf(0, "write_perm : 0x%#02x\n", char_md.p_cccd_md->write_perm);

and i get read_perm : 0x11 and write_perm : 0x11 it seems good.

[Geoffroy]

Hi marjeris,

I understand what you're telling me but it's in contradiction with my previous question : 

https://devzone.nordicsemi.com/f/nordic-q-a/46739/device-crash-when-adding-new-ble-service-ble-services-beginner-tutorial

and also with this other post : 

https://devzone.nordicsemi.com/f/nordic-q-a/12218/how-to-support-ble_gatts_vloc_user

[Marjeris Romero]

Hi Geoffroy,

See the last answer from Håkon in your previous question.

And the second post is using Softdevice S130 which is for nRF51 series, and is 3 years old so it's not valid for SDK v15.0.0 and nRF52840. The post was also only valid for serialization which we are not using in the tutorial.

Best Regards,

Marjeris

[Geoffroy]

yes i saw his answer thx.

but that was the way i could fix my problem...

And i saw that they replace BLE_GATTS_VLOC_STACK  by BLE_GATTS_VLOC_USER everywhere in code files but it's not a very nice solution, if there one line forgotten i can get troubles...  that's why i prefer use #define ...

however I'll try to do it your way...

[Marjeris Romero]

BTW, if you want more getting started material to look after this tutorial I would recommend taking a look at this repo next https://github.com/NordicPlayground/nRF52-Bluetooth-Course

Good luck!

[awneil]

Changing the values of the #defines is a Really Bad Idea !!

Because, when you do that, the name of the #define becomes a lie!

If you want to be able to quickly change the setting throughout your code, then do something like

#define MY_BLE_GATTS_VLOCK  BLE_GATTS_VLOC_STACK

and only use the MY_BLE_GATTS_VLOC in you code.

This is standard software engineering good practice - nothing specifically to do with Nordic.

[Geoffroy]

yes awneil i agree, i changed values in define for test but your way is better

[awneil]

Now you can verify the answers to your 2 threads