AnsweredAssumed Answered

Flow control with USB CDC or NACKING

Question asked by aounallah.mazen.001 on Dec 14, 2016
Latest reply on Dec 15, 2016 by shingadaddy


I'm trying to figure out a way to emulate UART  RTS / CTS flow control with the USB CDC. My main goal is to be able to tell the host to stop sending data if the µc is busy.

After a little googling I come up with some conclusions leading to more questions than results.

1/ Nacking is intrinsic in the CDC class but it seems that bintevall should be modified in the endpoint descriptor. is this true? if no how can we enable it and take control of it to use it for data flow control?

2/ Is Nacking possible when using Full speed devices or it is only for high speed devices?

3/In case of stopping the host from sending data, would that generate errors with the host size? is there a timeout that needs to be configured? and how can we tell the host to resume transmitting?

I'm sorry I asked too many questions. Any help would be much appreciated.