GL850 datasheet(18/40 Pages) ETC

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GL850 USB 2.0 4-Port HUB Controller

Page 18

5.1.11.2 Connected to USB2.0 Host/Hub

If an USB2.0 hub is connected to an USB2.0 host/hub, it will operate in USB2.0 mode. The upstream port

signaling is in high speed with bandwidth of 480 Mbps under this environment. The traffic channel will

then be routed to the REPEATER when the device connected to the downstream port is signaling also in

high speed. On the other hand, the traffic channel will then be routed to TT when the device connected to

the downstream port is signaling in full/low speed.

USB2.0 HOST/HUB

REPEATER

USPORToperating

in HS signaling

HS vs. FS/LS:

Traffic channel

is routed to TT

HS vs. HS:

Traffic channel is

routed to REPEATER

DSPORT operating

in HS signaling

DSPORT operating

in FS/LS signaling

Figure 5.2 - Operating in USB2.0 scheme

5.1.12 DSPORT logic

DSPORT (downstream port) logic implements the control logic defined in section 11.5 of USB specification

Revision 2.0. It mainly manipulates the state machine, the connection/disconnection detection, over current

detection and power enable control, and the status LED control of the downstream port. Besides, it also

output the control signals to the DSPORT transceiver.

5.1.13 DSPORT Transceiver

DSPORT transceiver is the analog circuit that supports high-speed, full-speed, and low-speed electrical

characteristics defined in chapter 7 of USB specification Revision 2.0. In addition, each DSPORT

transceiver accurately controls its own squelch level to detect the detachment and attachment of devices.

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