USB CDC ACM missing package

RE: USB CDC ACM missing package

weizhen — Tue, 19 Nov 2019 14:57:06 GMT

I can understand the part at the beginning when the chip start running. But in the end, what else can cause usb cdc do not print the message? we have the issue it lost several packages before rebooting.

RE: USB CDC ACM missing package

Kenneth — Mon, 18 Nov 2019 13:00:48 GMT

The UART can send data at any time, while for USB you need to wait until the host is ready. I suggest wait for APP_USBD_CDC_ACM_USER_EVT_PORT_OPEN event before pushing data on USB?

RE: USB CDC ACM missing package

weizhen — Thu, 14 Nov 2019 22:30:31 GMT

but then how about the package missing before reboot. it can print out by using uart only, but not with CDC

RE: USB CDC ACM missing package

Kenneth — Thu, 14 Nov 2019 20:31:06 GMT

I assume the easiest would be to wait for data received from the PC then, before you start sending data to the PC. Then you know the CDC driver and PC app have loaded on the PC is running before you start sending data. Could that work?

Else I think you just have to have a fixed delay after USB have enumerated before you start sending data to the PC.

RE: USB CDC ACM missing package

weizhen — Thu, 14 Nov 2019 17:13:53 GMT

lost from the UART to the PC

RE: USB CDC ACM missing package

Kenneth — Thu, 14 Nov 2019 14:17:12 GMT

Is the data lost from the PC to the UART, or lost from the UART to the PC?

Kenneth