at43312 ATMEL Corporation, at43312 Datasheet - Page 13

• Manufacturer Part Number: at43312
• Description: Self- And Bus- Powered Usb Hub Controller
• Manufacturer: ATMEL Corporation

Hub-specific Requests
Hub-specific requests or commands are sent from the Host
to the AT43312 using the Default Pipe (associated with
Endpoint0). These requests are made using control trans-
fers. The request and request parameters are sent in a
setup packet consisting of eight bytes. Please refer to the
USB specifications for details.
Clear_Hub_Feature
This request is used by the host to acknowledge local
power and hub overcurrent changes. Upon receipt of this
request with a wValue = 0, the AT43312 will clear the Local
Power Status Change bit. The AT43312 has a per port
overcurrent protection and does not report over-current on
a global basis. If this request has a wValue = 1, the
AT43312 will respond with a STALL.
Clear_Port_Feature
This request changes the status of a port according to
which port feature the request addressess. Not all the pos-
sible port features are supported, because some have no
m e a n i n g .
Clear_Port_Feature request are: PO RT_ENABLE,
PORT_SUSPEND, PORT_POWER, and all those affecting
the port status change bits. A request with an unsupported
feature, or if Port0 or a port higher than Port4 is addressed,
will cause the hub to respond with a STALL.
P o r t
f e a t u r e s
s u p p o r t e d
b y
t h e
Get_Bus_State
The AT43311 samples the bus states of Ports 1, 2, 3, and
4, at each EOF2 and will store the value in a register known
as the Port_Bus_State registers. The value of the D- signal
(pin DMx) will be in bit 0 and the value of the D+ signal
(DPx) will be in bit 1 of each port’s Port_Bus_State register.
All other bits will be 0. The AT43311 responds with a
STALL if Port0 or a port higher than Port4 is addressed in
this request.
Get_Hub_Descriptor
Retur ns the Hub De sc rip tor. The l ast word of the
Get_Hub_Descriptor request specifies the number of bytes
AT43312 is to return. If the requested number of bytes is
less than the 9 bytes length of the HubDescriptor, the
AT43312 will return only the requested number of bytes
from the top of the descriptor. If the requested number of
bytes is more than 9, then the returned data will be padded
with trailing bytes of zeroes.
Get_Hub_Status
Returns the current Hub status that has changed since the
previous acknowledgment in the form of two words of data.
This is described in the following two tables. Word0 is the
Hub Status Field, wHubStatus, and Word1 is the Hub
Change Field, wHubChange.
13