How to send more than 20 bytes using sd_ble_gatts_hvx

[valdev]

Hello,

I am looking for a way to send more than 20 bytes by using 'sd_ble_gatts_hvx' function. I want to get the maximum debit that is in theory 6x20 bytes Do I just have to send the set the p_len parameter to 6x20, because i didn't succeed through this way! I am using the S110 firmware and the nRF51-Dongle Thanks for you help

[Petter Myhre]

It is well described here.

Edit 16.10.2015

The point is that you can notify maximum 20 bytes with each call to sd_ble_gatts_hvx().

So you call this in a loop until it returns BLE_ERROR_NO_TX_BUFFERS, then you break out of the loop. Then you will get the BLE_EVT_TX_COMPLETE event when one or more packets have been sent. So then you loop sd_ble_gatts_hvx() again until you get BLE_ERROR_NO_TX_BUFFERS, and so on.

If you do this with the S110 you can get 6 packets in each connection interval because the TX buffer size is 6 (if the central device supports it).

[valdev]

Ok let me explain more myself. If i want to get the maximum rate I perform every 8ms an BLE sequence sending (in my dev only two sequences are enought), my understanding is after 8ms i will get an BLE_EVT_TX_COMPLETE which allow me to resend my other sequences. That s why I see the BLE_EVT_TX_COMPLETE appears every 8ms as a 8ms periodic signal can do!