USB On-the-Go:Negotiation process
HNP (Host Negotiation Protocol):
1. OTG-A (host) enables OTG-B (device) to become host by sending SetFeature (b_hnp_enable) command to OTG-B (device).
2. OTG-A (host) suspends bus signaling so that OTG-B (device) can
TM
now become host.
3.OTG-B (device) detects Suspend condition and turns off pull-up
resistor.
4.Because HNP is enabled, OTG-A (host) interprets this “disconnect” as a request by the OTG-B (device) to become host.
5.OTG-A (host) turns on its pull-up resistor and becomes peripheral/device.
Continued on the next slide
