how to add user description to characteristic

[wim]

Hi

I am implementing my custom service, and started from the led/button example. I am using the LightBlue app on my iphone to connect to my device under test. I can see the characteristics for the LED and button, but would like to add some kind of human readable description string as the label of a characteristic. I though I could do this by replacing the char_md.pa_char_user_desc = NULL by a pointer to a static string in the adding of the LED characteristic, but no luck:

...

//char_md.p_char_user_desc  = NULL;

static char user_desc[] = "LED";
char_md.p_char_user_desc  = (uint8_t *) user_desc;
char_md.char_user_desc_size = strlen(user_desc);
char_md.char_user_desc_max_size = strlen(user_desc);	

...

Any ideas? Do I need to assign something to char_md.p_user_desc_md? And how can I add a characteristic descriptor in general?

[Clem Taylor]

That is how I do it, here is my code:

if (description && *description != '\0')
{
    char_md.p_char_user_desc = (uint8_t*) description; // discards const 
    char_md.char_user_desc_size = strlen(description);  
    char_md.char_user_desc_max_size = char_md.char_user_desc_size;
}

I also played around with setting the char_pf stuff, but lightblue ignored it. Having the description text is useful for debug, not sure if I will leave it in the production firmware.

[Hung Bui]

Hi Wim,

I don't see any problem with your code, it worked on my side. Could you double check ? You can just leave char_md.p_user_desc_md = NULL;

Which error do you have when running your code ?

[wim]

Hi Hung Bui,

In fact, the Lightblue app did not update the device profile after I uploaded my new code. When I removed my device and stopped the app, and then started again, the characteristic was showing with the user description So problem solved!