Freescale-semiconductor TWR-MCF52259-Ethenet Bedienungsanleitung PDF herunterladen (Seite 129)

Introduction to USB

USB On-the-Go:

Negotiation process

Appendix A USB On-the-Go

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

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.

HNP (Host Negotiation Protocol):

Continued on the next slide 

1 2 ... 124 125 126 127 128 129 130 131 132 133 134 ... 165 166

Keine Kommentare

Freescale-semiconductor TWR-MCF52259-Ethenet Bedienungsanleitung Seite 129