DEVICE FOR USE AS STAND-ALONE DEVICE AND AS SLAVE DEVICE IN A DATA BUS SYSTEM

摘要

A device is provided for use in a data bus system like a USB bus system. The device (14) can be coupled to a host (10) via a bus cable (12) that comprises a data transfer conductor (124) and power supply conductors (120-122). The device (14) detects whether a power supply is connected to the power supply conductors (120-122). Dependent on whether or not connection of the power supply has been detected, device (14) starts operating in a slave mode or in a stand-alone mode respectively. In a slave mode the device (14) waits for commands received via the data transfer conductor. In the stand-alone mode the device (14) operates independent from communication via the cable. Preferably, the device signals back to the host whether it is in the slave mode by enabling pull-up of a potential of the data transfer conductor (124). In an embodiment, detection and signaling is controlled via a single control node (149).