The DS2490 is a bridge chip that enables communication between a USB host system and a 1-Wire bus. It provides regular, overdrive, and flexible 1-Wire communication speeds and a full-speed 12Mbps connection to USB. USB vendor-specific commands defined in this specification are used to control the DS2490 and communicate with attached 1-Wire devices. A functional block diagram of the DS2490 is shown in Figure 1.