The TUB (Timing and UART board) is a clock adapter board. It can transmit 1PPS and 10MHz clocks to four Terasic DE5a-NET boards simultaneously. The 1PPS and 10Mhz clocks are generated from an external clock generator. The TUB also provides a UART channel for four DE5a-NET boards to communicate with the host PC through the virtual COM port.

The TUB provides two channels of clock transfer function and one-USB-to-four-UART function. These two identical channels of clock transfer circuits support clock input signals with 1.2V, 1.8V, 2.5V, 3.3V, and 5V voltage levels. These two clock transfer channels also support zero bias clock with 1.2 Vpp, 1.8 Vpp, 2.5 Vpp, 3.3 Vpp, or 5 Vpp by soldering divider resistors. Each clock transfer channel provides four clock fan-outs for four DE5a-Net boards through the 2x5 cable.

TUB Connection with DE5a-NET Boards