Why is UUID in wrong order?

RE: Why is UUID in wrong order?

Oskar — Tue, 12 Jul 2016 12:59:47 GMT

Shouldn't 16bit uuids be instead of 13th and 14th bytes in base uuid? e.g. 0000-0100-59a4-4d2b-8479-8bbd-bcf7-7fcd for the service declaration uuid. Or even maybe 0000-0001-59a4-4d2b-8479-8bbd-bcf7-7fcd because of little endian core swaping (0x0001) to (0x0100) before pluging it to base.. I'm a bit confused.

RE: Why is UUID in wrong order?

Adam — Wed, 04 Mar 2015 15:23:13 GMT

I am sure I am flashing the correct file and the project compiles. Since then I started again from the UART example and checked every copied line and now it works just fine. I will try to search which line was causing the problem and post it later on. Thanks!

RE: Why is UUID in wrong order?

Vebjørn — Wed, 04 Mar 2015 14:24:40 GMT

This sounds very strange. If you modify the nus_base_uuid you should definitely see a change in the master control panel on your phone. Also, if all you have in the main function is service_init and advertisement_init, you shouldnt even be able to see the device at all. Are you sure you are flashing the correct file, and that the project compiles? (If it doesn't compile, it will flash the old hex file with the old UUID)

RE: Why is UUID in wrong order?

Nguyen Hoan Hoang — Wed, 04 Mar 2015 00:40:19 GMT

This is how the uuid is encoded

// UUID : 00000000-59a4-4d2b-8479-8bbdbcf77fcd
#define BLINKY_UUID_BASE {0xcd, 0x7f, 0xf7, 0xbc, 0xbd, 0x8b, 0x79, 0x84, 0x2b, 0x4d, 0xa4, 0x59, 0x0, 0x0, 0x0, 0x0}
#define BLINKY_UUID_SERVICE			1
#define BLINKY_UUID_CHAR			2

The service uuid would become 10000000-59a4-4d2b-8479-8bbdbcf77fcd

The characteristic uuid would become 20000000-59a4-4d2b-8479-8bbdbcf77fcd

The last 32bits of the base uuid will be replace by the one from the service or characteristic

RE: Why is UUID in wrong order?

Adam — Tue, 03 Mar 2015 18:01:09 GMT

That was my first thought too that is why I tried to modify the order of the UUID but it did not help. How do you change the Endian? Even when i set the UUID to 0s only, I received the wrong ID. No idea what is going on...

RE: Why is UUID in wrong order?

sroberts — Tue, 03 Mar 2015 17:55:21 GMT

Is your UUID being sent out in Big Endian format? I believe the Android app is looking for it in that format. I had a similar problem with the Company ID not being recognized, being "backwards", in reality, I was sending it out as Little Endian and not Big.