TM
USB Topology
Introduction to USB
USB On-the-Go:
Negotiation process
Appendix A USB On-the-Go
SRP (Session Request Protocol) Negotiations
OTG-B (device) asks OTG-A (host) for a USB OTG session by
signaling in one of two ways:
•
Pulsing an analog data line (D+ or D-), and
•
Pulsing V
BUS
through a relatively high impedance ( > 281 Ω
ΩΩ
Ω)
Note
: The B-device pulses data line first and then
pulses V
BUS