The ASM4242 is ASMedia’s first generation of Universal Serial Bus 4 (USB4®) host controller. It features upstream ports with 4-lane PCI Express 4.0 (PCIe Gen 4) and dual 4-lane DisplayPort sink ports, and downstream facing ports with dual USB4 ports. This controller also supports multiple protocol tunneling and USB 3.2 and DisplayPort alternate mode, providing high bandwidth up to USB4 Gen 3x2 40Gbps, USB 3.2 SuperSpeedPlus Gen 2x2 20Gbps and DisplayPort HBR3 x4 up to 32.4Gbps. This controller is in compliance with USB4 Specification Rev 1.0, VESA DisplayPort Standard V1.4a, VESA DisplayPort Alt Mode on USB Type-C Standard V2.0, and PCI Express Base Specification Rev 4.0 V1.0. Integrating ASMedia’s self-designed physical layers (PHYs), this controller is implemented with USB4 router including the time measurement unit (TMU) and several PCIe downstream/DisplayPort IN/USB downstream adapters, PCI Express switch, DisplayPort retimer and Intel® eXtensible Host Controller Interface. The xHCI host controller allows interfacing with USB 2.0 and USB 3.2. The 4-lane PCIe Gen 4 offers premium speed up to 16Gbps bandwidth per lane, and two DisplayPort ports up to 4 lanes with 8.1Gbps per lane. The two USB4 PHYs which support USB4 Gen 3/Gen 2, Thunderbolt 3 Gen 3/Gen 2, USB 3.2 Gen 2/Gen 1 and DisplayPort provide up to HBR3 level transmission rate. It also features PCI Express/USB/DP/Host Interface tunneling and is backward compatible with DisplayPort Alt mode and legacy USB 3.2/USB 2.0 devices, as well as in compliance with Thunderbolt 3. The ASM4242 uses flip chip technology in small form factor Green BGA package with advanced ultra-low power processing techniques. This complies with standard PCI Express/USB bus power management and advanced power management to reduce total power consumption efficiently under idle/standby state. This controller supports inbox driver of Microsoft® Windows 11 and various Linux™ kernels. Applications supported include motherboard, desktop PC, notebooks, workstations, servers and PCI Express based embedded systems.