It's a great retro feeling to use the amber VDU screen and PS/2 keyboard built into the FPGA. However, sometimes I prefer to use PuTTY on the USB serial terminal, particularly when I want to capture screens. But the use of the serial source jumper does present the possibility of confusion to which port is being used (VDU or USB serial).

Added auto-detection of the Serial port source. If the serSelect jumper (J3-1) is installed the USB is used. The serSelect is routed to the IOP16 CPU and checked. If USB is selected, the VDU screen shows "USB" added to the banner. This is useful to let the user know that the VDU is not being used.

Output on PuTTY: