max frame size USB BULK transmision/increase speed

[stevenB]

Hello,

I need to transfer a lot of data over USB. I configured the USB as a USB_CDC_ACM on the nrf52840.

Everything works but the problem that i'm running into is that I can't get the speed over 2.5 Mbits/second.

If I analyse the USB i can see that the frame package is 4096bytes. I'm trying to increase this value to get rid of all the overhead. I hope to increase the speed this way. But I can't find anywhere where to define it.

Is this a possible/ a correct way or is there maybe an other way to increase the speed?

[bjorn-spockeli]

Hi Steven,

based on tests with Windows we've seen that its the Windows CDC driver that limits the throughput. However, you should be able to get a throughput of 700kbps, i.e. 5.6 Mbps, using the MSC example, as described here

Best regards

Bjørn