NUS C and NUS "flow control"

[Fabien Comte]

Hello,

Few questions about NUS and NUS C please.

Is there any way to know how many TX are pending ?

Are TX notify or indicate ? How to change it please ?

Thank you

[Susheel Nuguru]

If you are trying to implement the BLE traffic flow control then the application can now configure packet counts per link, using the SV call sd_ble_cfg_set() with the cfg_id parameter set to BLE_CONN_CFG_GATTC and BLE_CONN_CFG_GATTS as shown here and then the application can keep track of how many tx buffers are free/full by locally counting(incrementing the transmit(TX) and decrementing the count when the app get BLE_GATTS_EVT_HVN_TX_COMPLETE

[Fabien Comte]

Ok I will try, thank you for your help. Few more questions please.

About notify or indicate ?

Do you know how many frame are exchanged at each connection interval ?

How to update connection interval on the fly ?

[Susheel Nuguru]

I think for notify, it is possible to send very fast if your application can fill the buffers full within the connection interval. But with indicate, it will be way slower since it is an app level acknowledgement. And when the app has to acknowledge, then a lot of latencies comes into picture. I do not think we can come with any generic number here.

[Fabien Comte]

Hello,

Sorry but my question is not about application level but NUS. Do you know if it use notify ir indicate ?

Thank you for your help.

[Susheel Nuguru]

Itis notifications are used. You can see that in SDK\components\ble\ble_services\ble_nus.c->ble_nus_init-> 

   add_char_params.char_props.notify = 1;