Uart RX packet loss for higher baudrate. What is maximum baudrate without packet loss for NRF52/SDK15/Softdevice 6.0.

[joy.kang]

Dear,

I see the Uart Rx packet loss at higher badurate, ie 460800, 921500, 1M.

I use NRF52, SDk15 with softdevice 6.0.

UART TX is no problem, but there is loss of RX packet. 

What is the maximum baud rate without packet loss ?

best regards,

Joey kang.

[joy.kang]

Hi. 

Please refer to the below.

I mean the remote is the wifi module.

I want to know what is the maximum baudrate without packet loss.

best regards,

Joey kang.

[awneil]

So how do you know that the packets are actually being lost in the nRF UART?

Or, to put it the other way around, how do you know that it's not your software that's losing the packets?

Are you using the UART via the SDK APIs, or accessing its hardware registers directly?

Remember that the nRF also has to run the BLE stack, and maintain BLE timing; so your software throughput - especially via the APIs - is limited...

[joy.kang]

Thank you awneil.

nRF52832 send back the received data to Wifi module, ie, echo mode.

I am using the UART via the SDK APIs.

So you mean I can use higher baudrate if I access the hardware registers directly. right ?

Br. Joey Kang.

[awneil]

You still don't seem to be getting the distinction between baud rate, and the data throughput that your software can manage.

I suspect that this is not a baud rate issue, but a limitation on the data throughput that your software can manage.

The SDK APIs will have a certain overhead. You may be able to do better with carefully-coded direct hardware access. But you then need to be careful not to "hog" the CPU - which could "startve" the BLE stack, and cause that to fail...

EDIT

Maybe DMA might help: https://devzone.nordicsemi.com/f/nordic-q-a/17232/nfr52-uart-with-dma ?