NCS peripheral uart increase data length

Question

Hello,

I use central_uart (nrf52840dk) and peripheral_uart (nrf52833dk) examples, NRF Connect SDK v1.6.0

I want to send more than 20 bytes of data,

So, I increase UART_BUF_SIZE 20 to 50, and when I send data from central device to peripheral It works well.

But I have no success sending more than 20 bytes from peripheral to central,

<wrn> bt_att: No ATT channel for MTU 25
<wrn> bt_gatt: No buffer available to send notification
<wrn> peripheral_uart: Failed to send data over BLE connection

Is it possible to send more than 20 bytes from both sides?

Thank you,

Anton

Karl Ylvisaker · Accepted Answer

Hello, 
 Is it possible to send more than 20 bytes from both sides? 
 It is, but you will need to increase the MTU size to be able to do so in a single transfer. The UART_BUF_SIZE is the size of the UART buffer, and does not have to do with the BLE MTU size, or the NUS service configuration. Please see this answer by my colleague Heidi for more information on how to do this in NCS v1.6.0 The summer holidays have begun here in Norway, and DevZone is therefore operating with reduced staff for the time being. Sorry for any inconvenience this might cause. Best regards, Karl

NCS peripheral uart increase data length

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