Two-Way Serial Communication with MinnnowBoard Max in Linux This tutorial explains how to set up two-way serial communication between a MinnnowBoard Max and a host computer running a Linux operating system. These instructions are based upon Ubuntu Linux and the serial terminal application ‘screen’, but other Linux environments and serial terminal applications with comparable functionality are also available to perform the same tasks. Connection between Host and Target Serial Cable to USB 1. You must have the appropriate USB 6 pin header cable to connect to the MinnowBoard Max. This is a USB to 3.3V TTL Header. You can purchase on the web by searching for the following part number: SS-TTL3VT . The cost is approximately $20 USD. August 15, 2014 Revision 1.0 1 To install screen 2. With root user permissions run the Advanced Packaging Tool to download and install the screen by running the following command from a terminal: sudo apt-get install screen August 15, 2014 Revision 1.0 2 3. The 6 pin header on the MinnowBoard Max serves as the serial port output: • Connect the other end (USB Type A ) to the USB port of your computer. • Note: Pin 1 of the Header is closest to the SATA connector. Pin 1 of the SS-TTL3VT cable is the Black lead wire. Pin 1 a. If you are running Linux in a virtual machine be sure that the virtual machine USB connection is active. b. Run the dmseg command from a terminal to determine which tty is created (typically ttyUSB0). c. Look for the FT230x Basic UART. d. Find the line that says FTDI USB Serial Device Converter now attached to ttyUSBX, where X is the assigned number. August 15, 2014 Revision 1.0 3 August 15, 2014 Revision 1.0 4 To start screen for MinnnowBoard Max serial communication purposes 1. Make sure to have root user permission and execute the command: screen /dev/ttyUSBX 115200 a. Replace the X of USBX with the actual assigned tty number found during the previous step. The 115200 indicates the baud rate for the serial data transfer. Two-way serial communication should now be established between the MinnnowBoard Max and host computer. Type into the terminal to communicate with the MinnnowBoard Max UEFI Shell. August 15, 2014 Revision 1.0 5