AT43312 Datasheet, PDF (7/21 Pages) ATMEL Corporation – Self- and Bus- Powered USB Hub Controller

AT43312
Endpoint0
Endpoint0 is the AT43312’s default endpoint used for enu-
meration of the Hub and exchange of configuration infor-
mation and requests between the Host and the AT43312.
Endpoint0 supports control transfers.
The Hub Controller supports the following descriptors:
Device Descriptor, Configuration Descriptor, Interface
Descriptor, Endpoint Descriptor, and Hub Descriptor.
These Descriptors are described in detail on page 9
through page 16 of this document. Standard USB Device
Requests and class-specific Hub Requests are also sup-
ported through Endpoint0. There is no endpoint descriptor
for Endpoint0.
Status Change Register
Bit Function
Value Meaning
0 Hub status change
0 No change in status
1 Change in status detected
1 Port1 status change 0 No change in status
1 Change in status detected
2 Port2 status change 0 No change in status
1 Change in status detected
3 Port3 status change 0 No change in status
1 Change in status detected
4 Port4 status change 0 No change in status
1 Change in status detected
5-7 Reserved
000 Default values
An IN Token packet from the Host to Endpoint1 indicates a
request for port change status. If the Hub has not detected
any change on its ports, nor any changes in itself, then all
bits in this register will be 0 and the Hub Controller will
return a NAK to requests on Endpoint1. If any of bits 0-4 is
1, the Hub Controller will transfer the whole byte. The Hub
Endpoint1
Endpoint1, an interrupt endpoint, is used by the Hub Con-
troller to send status change information to the Host.
The Hub Controller samples the changes at the end of
every frame at time marker EOF2 in preparation for a
potential data transfer in the subsequent frame. The sam-
pled information is stored in a byte-wide register, the Status
Change Register, using a bitmap scheme.
Each bit in the Status Change Register corresponds to one
port as shown below:
Controller will continue to report a status change when
polled until that particular change has been removed by a
Clear_Port_Feature request from the Host. No status
change will be reported by Endpoint1 until the AT43312
has been enumerated and configured by the Host via
Endpoint0.
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