XON / XOFF on nordic DK

[tc_2020]

Hello,

I have an xon / xoff flow control implementation with nRF52833 DK.

The setup is the nRF52833 DK is connected to the computer through USB cable.

A python script is running on my computer which transmits serial frame to the DK at random time. PySerial is used and the port (JLINK CDC Uart port) is opened with xonxoff feature enabled.

The DK sends XOFF every 10 ms and send XON 1ms after to stop and resume the serial frame transmission.

Through serial debugger and logic analyzer, I confirm that the nRF52833 has sent out the xoff (0x13) however, the transmission never stops. The DK continuously received the incoming serial frame. I want to check the driver of the Jlink CDC UART PORT does support the xon xoff feature? 

Tengfei

[Sigurd]

Hi,

PySerial is used and the port (JLINK CDC Uart port) is opened with xonxoff feature enabled.

 The DK supports flow-control RTS/CTS. https://infocenter.nordicsemi.com/topic/ug_nrf52833_dk/UG/dk/vir_com_port.html

Could you configure PySerial to use rtscts instead, and see if that makes a difference?

[tc_2020]

Hi, Thanks for the reply!

We are using the RTS/CTS to control our board so we disabled the RTS/CTS feature. 

Does it mean the xon/xoff feature is not supported with the DK USB driver? 

[Sigurd]

tc_2020 said:

Does it mean the xon/xoff feature is not supported with the DK USB driver? 

 Well, xonxoff is software flow control ,and rtscts/dtsdtr is hardware flow control. As far I know, you would need to handle xonxoff commands in your application yourself, and stop/start transmission based on the signals you send/receive.