sending data over ble

[sowmya]

Hello,

I have developed a simple characteristic to send data over ble using the ble_nus service. I created a service and added a characteristic to send. Then sending the counter data (eg: 1 to 100 decimal value), one byte per second and I am testing using MCP.

It is able to connect and bond and also I am able to see the characteristic which I have added. But I am not able to see the data.

Do I have to configure any to send data over ble?

Regards,

Sowmya

[Bill Siever]

If the characteristic is properly configured as readable, then you can poll for the data (read it).

If you want push-style data updates (an update is sent every time there's new data), the characteristic will need to support either indications or notifications as well as have a client characteristic configuration descriptor (CCCD) to allow the client to opt-in to receive the updates. I'm guessing that you haven't used the MCP to enable the notifications/indications on the characteristic.

See the other posts on the CCCD, indications or notifications. There are also several examples in the SDK.

[sowmya]

I configured the CCCD to receive characteristic and it is working. I had used MCP to enable notification.

[sowmya]

Hi, one more question is, how to send more than 20 bytes of data? I changed the variable length and also maximum length in GATTS structure but it is not working. Can anyone guide me?

[MartinBL]

There are several threads regarding this here on devzone, e.g. this and this.

[sowmya]

Yes I searched in forum and I am able to send more than 20 bytes. Now I need to go for long write. I will open one more thread regarding long write. Thank you all.