Discovering characteristic values

Gergo Zsiak

Hi All,

According to the GATT documentation the function GATT_DiscCharsByUUID is used to discover characteristic values depending on the given UUID's. However, in the original SimpleBLEcentral project it is done by a GATT_ReadUsingCharUUID call, and once a response received, the handle is stored.

Is there any difference between the two ways?

I am working on a project where 4 charvs should be discovered, however, at the first step an error is received which says "No attribute found within the given attribute handle range". I think the UUID and the GATT profile are correct, and trying to figure out the reason of the error.

Thanks,

Gergo

over 14 years ago

0 J Lindh over 14 years ago

TI__Guru 57865 points

Hi Gergo,

GATT_ReadUsingCharUUID:

This sub-procedure is used to read a Characteristic Value from a server when the client only knows the characteristic UUID and does not know the handle of the characteristic.

GATT_DiscCharsByUUID:

This sub-procedure is used by a client to discover service characteristics on a server when only the service handle ranges are known and the characteristic UUID is known.The specific service may exist multiple times on a server.The characteristic being discovered is identified by the characteristic UUID.

0 kazola over 14 years ago in reply to J Lindh

Guru 18625 points

In a quick way, I use to match the word "read" to "handle" and the word "discover" to "char".

I hope it works for you :) Bye.

0 Gergo Zsiak over 14 years ago in reply to J Lindh

Intellectual 855 points

Hi Nick,

I've read the documentation, I just wanted to figure out, what's the reason of using GATT_ReadUsingCharUUID in the sample projects.

Thanks,

Gergo

0 J Lindh over 14 years ago in reply to Gergo Zsiak

TI__Guru 57865 points

Hi Gergo,

Because in a real implementation you wouldn't know the handles of the peripheral, I guess. This is just an example what to do, you can choose either way :)

0 Gergo Zsiak over 14 years ago in reply to J Lindh

Intellectual 855 points

OK, I see.

Thanks,

Gergo

0 Hafiz Ahmed over 13 years ago in reply to J Lindh

Intellectual 300 points

Hi,

Since we don't know the handles of the peripheral in a real implementation, how can we use the function GATT_WriteCharValue( simpleBLEConnHandle, &reqw, simpleBLETaskId ); because we need to define the reqw.handle?

I'm trying to write data to multiple characteristics.

Thanks in advance for your help

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Discovering characteristic values