| 摘要 |
PROBLEM TO BE SOLVED: To provide a data transfer control unit or the like that is capable of switching the VBUS power feeding voltage. SOLUTION: A transfer controller 10 transmits a VBUS power feeding voltage switching request packet to a B plug connection side (B device side), and when a switching consent packet is received, switching from ordinary voltage power feeding to low voltage power feeding is instructed to a power feeding switch circuit 30. Monitoring of a VBUS ordinary voltage level is then stopped, and monitoring of a VBUS low voltage level is started, A transfer controller 50 receives a VBUS power feeding voltage switching request packet from an A plug connection side (A device side); and when consenting to switching, a switching consent packet is transmitted. Monitoring of the VBUS normal voltage level is then stopped, and monitoring of the VBUS low voltage level is started. The switching request packet or the switching consent packet is transmitted by control transfer. COPYRIGHT: (C)2005,JPO&NCIPI
|
