Accessing the Morello console

You can manage the Morello board, including reaching its multiple serial consoles and firmware flash storage, via a USB cable connected to a second computer -- typically a workstation or remote management server. When you plug the USB cable into your workstation, a number of different devices will attach (depending on device drivers on your workstation), including:

  • Arm Morello USB debug and trace
  • Flash storage used for firmware (an on-board SD card)
  • Two 4-port USB-to-serial converters

Each controller has a unique serial number ending in the letter "A" or B". The serial-port converters attach to UARTs associated with:

  • The MCC management microcontroller (converter B port 0)
  • The PCC management microcontroller (converter B port 1)
  • The Morello system console (converter B port 2)

In normal use, only the MCC and Morello system console ports will be used. You can connect to these using a serial access tool such as cu(1), or a full terminal emulation environment such as screen(1). The precise names of the /dev device nodes appearing on the workstation depend on the operating system being used. Often access will also require running the terminal command under su(8) or sudo(8), or adding your user to a dialer or similar group to grant access to the USB device nodes.

Connecting from FreeBSD

FreeBSD names USB device nodes in the order they probe and attach. Typical command lines to access the MCC and Morello consoles are:

  • MCC console: cu -l /dev/cuaU0 -s 115200
  • Morello console: cu -l /dev/cuaU2 -s 115200

Connecting from Apple macOS

macOS creates /dev/cu.usbserial- device nodes that embed the device serial number (including A or B) and port number. Typical command lines to access the MCC and Morello consoles are:

  • MCC console: cu -l /dev/cu.usbserial-00FT41683097B0 -s 115200
  • Morello console: cu -l /dev/cu.usbserial-00FT41683097B2 -s 115200

You will need to substitute the serial numbers of the USB converters in your specific Morello board for these commands to work.

Connecting from Windows

Windows requires the installation of FTDI drivers to access the Morello board's USB ports, and the OS should identify the appropriate driver version once the board is connected. Plink is a CLI bundled with PuTTY, a third-party terminal emulator and SSH client freely available from the Windows Store and the developer's official website. After installing the drivers and PuTTY, typical command lines to access the MCC and Morello consoles are:

  • MCC console: plink -serial \\.\COM3 -sercfg 115200
  • Morello console: plink -serial \\.\COM5 -sercfg 115200

Do note that Windows assigns serial numbers at random.