adding characteristic to a service

[wolfman24]

I'm sorry but i don't know where else to turn. The tutorial on adding a characteristic to a service (the nordic tutorial i am basing this off) isn't finished and I have no one to ask but the internet. I have tried copying code and applying it myself but there's always some problem that never gets it working.

I can make a service just fine because of [this] (devzone.nordicsemi.com/.../) tutorial and I understand all the steps for making a characteristic, at least i am pretty sure I do, but I can't seem to figure out how to put the code in the right place. I have my main, service_maker.c, and service_maker.h

I really need help. I've been at this for too long and its driving me insane. I tried comparing to to other code but the functions are either return uint32_t or lead to other functions that involve things I simply don't have the time to learn. Please help.

main service init()

static void services_init(void)
{
    our_service_init(&main_ble_oss_char_type);
{

service_maker.c

void our_service_init2(ble_oss_char_type * p_our_service)
{
    uint32_t   err_code; // Variable to hold return codes from library and softdevice functions
    ble_uuid_t        service_uuid;
	ble_uuid128_t     base_uuid = BLE_UUID_OUR_BASE_UUID;
	service_uuid.uuid = BLE_UUID_OUR_SERVICE;
	err_code = sd_ble_uuid_vs_add(&base_uuid, &service_uuid.type);
	APP_ERROR_CHECK(err_code);

    // OUR_JOB: Declare 16 bit service and 128 bit base UUIDs and add them to BLE stack table     

																 
    // OUR_JOB: Add our service

	err_code = sd_ble_gatts_service_add(BLE_GATTS_SRVC_TYPE_PRIMARY,
                                &service_uuid,
                                &p_our_service->service_handle);
}


void our_char_add(ble_oss_char_type * p_our_service){
    uint32_t							err_code;

	ble_uuid_t          char_uuid;
	ble_uuid128_t       base_uuid = BLE_UUID_OUR_BASE_UUID;
	char_uuid.uuid      = BLE_UUID_OUR_CHARACTERISTC_UUID;
	sd_ble_uuid_vs_add(&base_uuid, &char_uuid.type);
	APP_ERROR_CHECK(err_code);

	ble_gatts_attr_md_t attr_md;
	memset(&attr_md, 0, sizeof(attr_md));
	attr_md.vloc        = BLE_GATTS_VLOC_STACK;

	ble_gatts_attr_t    attr_char_value;
	memset(&attr_char_value, 0, sizeof(attr_char_value));    
	attr_char_value.p_uuid      = &char_uuid;
	attr_char_value.p_attr_md   = &attr_md;
	ble_gatts_char_md_t char_md;


	err_code = sd_ble_gatts_characteristic_add(p_our_service->service_handle,
                               &char_md,
                               &attr_char_value,
                               &p_our_service->char_handles);
    APP_ERROR_CHECK(err_code);

}

and then service_maker.h

typedef struct ble_oss ble_oss_char_type;

struct ble_oss
{
    uint16_t                    conn_handle;    //< Handle of the current connection (as provided by the BLE stack, is BLE_CONN_HANDLE_INVALID if not in a connection).
    uint16_t                    service_handle; //< Handle of Our Service (as provided by the BLE         stack).
    // OUR_JOB: Add handles for our characteristic
    ble_gatts_char_handles_t    char_handles;
};
    void our_service_init(ble_oss_char_type * p_our_service);

    void our_char_add(ble_oss_char_type * p_our_service);

I know I can't be the only one out there who could benefit from a good answer here. Thank you so much and i really appreciate any help you offer

[Ulrich Myhre]

First of all, you should figure out what the return code (err_code) is. There are multiple ways to go from there. You could be out of memory, the parameters could also be invalid. Adding this information to your question will narrow it down by a lot.

[Anders Strand]

Hello.

You should first add the service using sd_ble_gatts_service_add and then add all its characteristics using sd_ble_gatts_characteristic_add. So in your case, you should call our_char_add on the bottom of our_service_init2. Make sure that the service was initialized successfully before adding your characteristic.

See part 3.6 and 4.4 of the "Creating Bluetooth Low Energy Applications Using nRF51822". application note.

It was a bit unclear what you were uncertain about. Please try to specify what you want to know if you want a more detailed explanation. If things are not working, you can note which error code was returned by which function. You can then search this forum for the error code, or ask about it in a comment or in a new thread.

-Anders