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UUID in PSoC BLE | Cypress Semiconductor


Summary: 5 Replies, Latest post by martin.thuering_1536551 on 14 Jul 2016 06:02 AM PDT
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rfc_1549836's picture
25 posts

I'm building a simple central BLE application, with two pioneer kits. For services management, I use Ble_GattcDiscoverPrimaryServiceByUuid() API to get the service know by UUID.

If UUID is 16 bits long the function work and the events CYBLE_EVT_GATTC_FIND_BY_TYPE_VALUE_RSP followed by CYBLE_EVT_GATTC_ERROR_RSP returns.

The structure and initialization of UUID is:

View attachment, because spam filter block my code :( :( :(

The UUID on peripheral side is 0xff11, so I think that the little-endian format is adopted for memory order.

If I use 128 bits UUID (of course both for central and peripheral) I don't have the CYBLE_EVT_GATTC_FIND_BY_TYPE_VALUE_RSP event, but only CYBLE_EVT_GATTC_ERROR_RSP and no data returns.


/* structure to be passed for discovering service by UUID */
const CYBLE_GATT_VALUE_T    SNSrvUuidInfo = {
                                                        (uint8 *) SNSrv, \
                                                        CYBLE_GATT_128_BIT_UUID_SIZE \


In this case the UUIS initialization and structure are:
//  UUID :    00   00   ff   11   00   00   10   00   80   00   00   80   5f   9b   34   fb
const uint8 SNSrv[16] =     { 0xfb, 0x34, 0x9b, 0x5f, 0x80, 0x00, 0x00, 0x80, \
                              0x00, 0x10,0x00, 0x00, 0x11, 0xff, 0x00, 0x00 };

Even in this case the UUID, showed in peripheral's custom service (0000ff11-0000-1000-8000-00805F9B34FB), is written on reverse order in structure.

Where is my mistake, why the 128 bit version doesn't work?
Thanks, Fabrizio

operationred1991_1569406's picture
51 posts

Can you try with the UUID array in the reverse order?

rfc_1549836's picture
25 posts

already done. It doesn't work.



Hi Fabrizio

I have exactly the same problem as you do. Were you able to solve it?

best regards


rfc_1549836's picture
25 posts

Not yet solved. For now I've skipped the problem, but I have to return on it. I'll post the solution if I found.

ok thanks for the reply

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