RE: Discovering and connecting to BLE devices with custom 128 bit UUIDs using Zephyr

JPSvanderWalt — Wed, 04 Nov 2020 11:31:09 GMT

Thank you haakonsh I was not sure if the Discovery Manager differentiates between different sizes of UUIDs. I will see if I can get it up and running. Your help is much appreciated.

RE: Discovering and connecting to BLE devices with custom 128 bit UUIDs using Zephyr

haakonsh — Wed, 04 Nov 2020 10:15:59 GMT

There's no difference between 16-bit and 128-bit UUIDs with regards to the Discovery Manager's API:

You declare the custom UUID with:

#define MY_SERVICE_UUID 0xd4, 0x86, 0x48, 0x24, 0x54, 0xB3, 0x43, 0xA1, \
			            0xBC, 0x20, 0x97, 0x8F, 0xC3, 0x76, 0xC2, 0x75
			            
#define BT_UUID_MY_SERVICE      BT_UUID_DECLARE_128(MY_SERVICE_UUID)

And call:

bt_gatt_dm_start(conn, BT_UUID_MY_SERVICE, &discovery_cb, NULL);

The second parameter of bt_gatt_dm_start is of type bt_uuid:

/** @brief This is a 'tentative' type and should be used as a pointer only */
struct bt_uuid {
	u8_t type;
};

You are however supposed to pass any of the following types:

struct bt_uuid_16 {
	struct bt_uuid uuid;
	u16_t val;
};

struct bt_uuid_32 {
	struct bt_uuid uuid;
	u32_t val;
};

struct bt_uuid_128 {
	struct bt_uuid uuid;
	u8_t val[16];
};