Custom UART BLE Read fails

RE: Custom UART BLE Read fails

Lodge — Thu, 10 Sep 2015 09:10:43 GMT

Hi Alex, I am not sure how that worked, but I have added the notification and it works now. I am using Visual C++, not cs and there is a good example of how to do it here in case anyone is interested link text It works great now, thanks so much

RE: Custom UART BLE Read fails

Alex — Wed, 09 Sep 2015 11:01:28 GMT

I understand that your PC is master/client and nRF51 is slave/server. In that case client can read data from server but server can't send data directly, only using notification/indication. I don't understand how your lost nrf code could initiate sending data without notification enabled.

RE: Custom UART BLE Read fails

Lodge — Wed, 09 Sep 2015 10:37:29 GMT

Hi Alex, Thanks again for all the information and I am sorry for all the questions. Is this the only way to send data to the application? The reason I ask is I had the communication working perfectly, but lost the nrf project code when my PC crashed. I have the original windows App code and I didn't have to enable notifications. I have re-written the nrf51 code, but am getting the above error. Is there a way to send data to the server without notifications? I only need to read about 100 bytes of configuration data on connection from the app, and I don't need to notify when it gets changed. Again, thanks for all the help.

RE: Custom UART BLE Read fails

Alex — Wed, 09 Sep 2015 09:11:00 GMT

Short and nice explanation is here

RE: Custom UART BLE Read fails

Lodge — Wed, 09 Sep 2015 09:06:18 GMT

Hi Alex, Thanks again. I will try that. Out of interest, you mention you can send data to master either by notification or indication. Could you explain how indication works? Much appreciated.

RE: Custom UART BLE Read fails

Alex — Wed, 09 Sep 2015 08:57:23 GMT

In W8 you can enable notification by:

gatt_characteristic.WriteClientCharacteristicConfigurationDescriptorAsync(
                                            CHARACTERISTIC_NOTIFICATION_TYPE);

where

gatt_characteristic = service.GetCharacteristics(UUIDofcharacteristic)[0];

and service = await GattDeviceService.FromIdAsync(deviceId);

RE: Custom UART BLE Read fails

Alex — Wed, 09 Sep 2015 07:49:05 GMT

Why don't you enable notification in Windows 8 application? This is how data send from device to master, either by notification or indication. Give me some time, I'll find the command which enables notification in our W8 code

RE: Custom UART BLE Read fails

Lodge — Wed, 09 Sep 2015 07:38:40 GMT

Hi Alex, Thanks for the reply. Does this mean that I have to enable notifications from the master side before I can send data to it? What I am doing at the moment is sending data to the device from a custom windows 8 application with a read command. I then want to send about 5 packets of data back to the master. This is failing when I call the SendString command for the above reason. Is there a way to do this without enabling notifications? Thanks very much, Lodge.

RE: Custom UART BLE Read fails

Alex — Tue, 08 Sep 2015 15:53:26 GMT

That part of the code called when you enable notification from master. For example in Master Control Panel in Android connect to your device, choose service and then on right hand side of characteristic you will see three down arrows. Press on them and notification will be enabled. If you are using your own application then you need to enable notification in your application before the first SendString used in the device