RE: User description descriptor write event missing UUID and data

Amanda Hsieh — Wed, 27 Nov 2019 06:44:07 GMT

Great to hear that. Thanks for sharing. 🙂

Amanda H.

RE: User description descriptor write event missing UUID and data

bfriedk1 — Tue, 26 Nov 2019 23:06:27 GMT

Hello -

After a little more digging, I was able to find a configuration setup that works. It still seems necessary for the p_char_user_desc field to point at a non-NULL buffer. But if I set the is_defered_read and is_defered_write fields fields to 0, the SDK triggers a BLE_GATTS_EVT_WRITE event, where I can capture the data written. Here is the updated user descriptor initialization code that works for me:

ble_add_char_params_t add_char_params;
ble_add_char_user_desc_t add_user_desc;
uint8_t buffer[64];

add_user_desc.max_size = 64;
add_user_desc.size = 0;
add_user_desc.p_char_user_desc = buffer;
add_user_desc.is_var_len = 1;
add_user_desc.is_defered_read = 0;
add_user_desc.is_defered_write = 0;
add_user_desc.is_value_user = 1;
add_user_desc.char_props.read = 1;
add_user_desc.char_props.write = 1;
add_user_desc.char_props.write_wo_resp = 0;
add_user_desc.char_props.notify= 0;
add_user_desc.char_props.indicate= 0;
add_user_desc.read_access = SEC_OPEN;
add_user_desc.write_access = SEC_OPEN.
add_char_params.p_user_descr = &add_user_desc;

Note that the behavior is different compared to characteristics, where I can set the p_init_value field to NULL and the defered fields to 1.

Regards,

Brian

RE: User description descriptor write event missing UUID and data

Amanda Hsieh — Tue, 26 Nov 2019 14:41:11 GMT

Hi,

Please see this BLE Characteristics-a-beginners-tutorial. It can help you.

-Amanda H.