Freescale Semiconductor TWR-MCF52259-Ethenet User Manual page 128

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
:
Note
The B-device pulses data line first and then
pulses V
Introduction to USB
through a relatively high impedance ( > 281 Ω Ω Ω Ω )
BUS
BUS
Negotiation process
TM