zephyr/samples/subsys/usb/cdc_acm_composite
Johann Fischer 67a265b0df samples: cdc_acm: check return value of uart_fifo_read()
uart_fifo_read() can return negative values in case
it is not implemented or CONFIG_UART_INTERRUPT_DRIVEN
is not enabled. Both cases can not actually happen in the
case of CDC ACM UART, check it anyway in case behavior
of the UART API changes unnoticed.

Align the code in RX path code of both camples and
enable TX interrupt only if data was received successfully.

Fixes: #39835
Fixes: #39824
Fixes: #39809
Coverity-CID: 240667
Coverity-CID: 240679
Coverity-CID: 240697

Signed-off-by: Johann Fischer <johann.fischer@nordicsemi.no>
2021-11-24 10:50:11 +01:00
..
src samples: cdc_acm: check return value of uart_fifo_read() 2021-11-24 10:50:11 +01:00
app.overlay samples: usb: get CDC ACM UART device from devicetree 2021-08-23 18:53:47 -04:00
CMakeLists.txt cmake: increase minimal required version to 3.20.0 2021-08-20 09:47:34 +02:00
Kconfig
prj.conf samples: usb: get CDC ACM UART device from devicetree 2021-08-23 18:53:47 -04:00
README.rst
sample.yaml

.. _usb_cdc-acm_composite:

USB CDC ACM Sample Composite Application
########################################

Overview
********

This sample app demonstrates use of a USB Communication Device Class (CDC)
Abstract Control Model (ACM) driver provided by the Zephyr project in
Composite configuration.

Two serial ports are created when the device is plugged to the PC.
Received data from one serial port is sent to another serial port
provided by this driver.

Running
*******

Plug the board into a host device, for example, a PC running Linux.
The board will be detected as shown by the Linux dmesg command:

.. code-block:: console

   usb 1-1.5.4: new full-speed USB device number 28 using ehci-pci
   usb 1-1.5.4: New USB device found, idVendor=2fe3, idProduct=0002, bcdDevice= 2.03
   usb 1-1.5.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3
   usb 1-1.5.4: Product: Zephyr CDC ACM Composite sample
   usb 1-1.5.4: Manufacturer: ZEPHYR
   usb 1-1.5.4: SerialNumber: 86FE679A598AC47A
   cdc_acm 1-1.5.4:1.0: ttyACM1: USB ACM device
   cdc_acm 1-1.5.4:1.2: ttyACM2: USB ACM device

The app prints on serial output, used for the console:

.. code-block:: console

   Wait for DTR

Open a serial port emulator, for example, minicom,
and attach it to both detected CDC ACM devices:

.. code-block:: console

   minicom --device /dev/ttyACM1
   minicom --device /dev/ttyACM2

The app should respond on serial output with:

.. code-block:: console

   DTR set, start test
   Baudrate detected: 115200
   Baudrate detected: 115200

And on ttyACM devices provided by the Zephyr USB device stack:

.. code-block:: console

   Send characters to another UART device

The characters entered in one serial port will be sent to another
serial port.