characteristic value as a structure

[Anjaly]

Hello, I am working with S130 softdevice. I am using SDK v6. I want to send multiple data as a single characteristic value (possibly as a structure). But it is seen that p_value in ble_gatts_attr_t is uint8_t*. Can I modify it to a structure pointer?? Or is there any other way to solve the problem???

Anybody came across with a similar situation???

Thanks in advance

[John]

I had the opposite problem when receiving our proprietary commands on a characteristic. It was relatively simple to create a pointer to a structure of our command and then assign it the address of the uint8 * in the write event. It looks like:

    ble_gatts_evt_write_t	* p_evt_write = &p_ble_evt->evt.gatts_evt.params.write;
    onset_recv_command_t	* p_received_command = (onset_recv_command_t *)&p_evt_write->data[0];

You could do the opposite and fill in your structure and then assign the address to your uint8_t pointer for your write command.

[ovrebekk]

I believe the two most common ways to solve this issue is:

a) As John says you could always cast your struct pointer to a uint8_t pointer, and assign it to p_value.

b) Declare your struct as a union between a uint8_t array and a sub-struct containing all your fields. Then you can refer to the uint8_t array when passing the data to the BLE stack, and refer to the sub-struct when assigning your data fields.

[Anjaly]

Thank you for your reply.

[kerem]

Thanks for the union hint.