README.md



System / cdcacm USB CDC/ACM serial

This very simple add-on allows the USB CDC/ACM serial device can be dynamically
connected and disconnected from a host. This add-on can only be used as an NSH
built-in command. If built-in, then two new NSH commands will be supported:


sercon – Connect the CDC/ACM serial device

serdis – Disconnect the CDC/ACM serial device


Configuration prerequisites (not complete):


CONFIG_USBDEV=y – USB device support must be enabled

CONFIG_CDCACM=y – The CDC/ACM driver must be built


Configuration options specific to this add-on:


CONFIG_SYSTEM_CDCACM_DEVMINOR – The minor number of the CDC/ACM device,
i.e., the x in /dev/ttyACMx.


If CONFIG_USBDEV_TRACE is enabled (or CONFIG_DEBUG_FEATURES and
CONFIG_DEBUG_USB, or CONFIG_USBDEV_TRACE), then the add-on code will also
initialize the USB trace output. The amount of trace output can be controlled
using:


CONFIG_SYSTEM_CDCACM_TRACEINIT – Show initialization events.

CONFIG_SYSTEM_CDCACM_TRACECLASS – Show class driver events.

CONFIG_SYSTEM_CDCACM_TRACETRANSFERS – Show data transfer events.

CONFIG_SYSTEM_CDCACM_TRACECONTROLLER – Show controller events.

CONFIG_SYSTEM_CDCACM_TRACEINTERRUPTS – Show interrupt-related events.


Note: This add-on is only enables or disable USB CDC/ACM via the NSH
sercon and serdis command. It will enable and disable tracing per the
settings before enabling and after disabling the CDC/ACM device. It will not,
however, monitor buffered trace data in the interim. If CONFIG_USBDEV_TRACE is
defined (and the debug options are not), other application logic will need to
monitor the buffered trace data.