Detachable adapter and portable system

A portable system, comprising:

• a portable device, which comprises:
• a bus controller for providing and controlling a host data bus;
• a receptacle for coupling the host data bus to an external device;
• a connection status detection circuit, coupled to the receptacle of the portable device, for determining external coupling status of the host data bus and generating an event signal;
• and
• a microprocessor for controlling the portable device, wherein the microprocessor performs power control in response to the event signal;
• and
• an adapter detachably connected to the host data bus of the receptacle of the portable device, wherein the adapter comprises:
• a first receptacle, detachably coupled to a first data bus of a client device;
• a second receptacle, detachably coupled to a second data bus of a power supply device;
• a plug, detachably coupled to the host data bus of the receptacle of the portable device, for providing a set of host bus signals on the host data bus of the portable device, wherein the set of host bus signals comprises a data signal, a connection status signal, and a power signal, and at least one signal line of the first data bus of the first receptacle is coupled to the host data bus of the plug to serve as at least the data signal of the set of host bus signals;
• a conversion circuit, coupled to the second receptacle, for providing the set of host bus signals on the plug according to at least a signal obtained from the second data bus, and determining whether the power supply device is connected to the second receptacle according to the at least one signal obtained from the second data bus, and providing the connection status signal on the plug so that the portable device obtains connection status of the adapter, wherein:
• if the conversion circuit determines that the power supply device is connected to the second receptacle, the conversion circuit outputs a power signal, obtained from the second data bus, to the plug to serve as the power signal of the host bus signals, and outputs the power signal to the first receptacle to serve as a power signal of the first data bus;
• and
• the connection status detection circuit of the portable device receives the connection status signal to generate the event signal, and when the connection status signal indicates a first connection status for representing that the adapter is connected to the portable device and the power supply device, the microprocessor of the portable device, according to the event signal, determines whether to power or charge the portable device by the power signal of the host bus signals.