Patent ID: 8850097

Claim:
USB apparatus suitable for interconnection with a USB host having a D− bus coupled to ground via a pull-down resistance, said USB apparatus comprising: a microcontroller having a first port and a second port, said first port being coupled via a resistance to a voltage source; and a switch, operated by said microcontroller via said second port, selectably interconnecting said first port and said D− bus of said USB host, when said USB apparatus is connected to said USB host, said microcontroller, when operative in a connection detection mode, being operative to: supply a predetermined voltage to said second port, thereby closing said switch and thereby interconnecting said first port and said D− bus of said USB host, when said USB apparatus is connected to said USB host; and monitor a voltage at said first port, which voltage indicates connection of said USB apparatus with said USB host by virtue of a voltage drop at said first port produced by current flow from said first port via said switch and across said pull-down resistance to ground.