CY7C656XX CYPRESS [Cypress Semiconductor], CY7C656XX Datasheet - Page 3

• Manufacturer Part Number: CY7C656XX
• Manufacturer: CYPRESS [Cypress Semiconductor]

Document #: 38-08037 Rev. *H
Hub Repeater
The Hub Repeater manages the connectivity between
upstream and downstream facing ports that are operating at
the same speed. It supports full-/low-speed connectivity and
high-speed connectivity. According to the USB 2.0 specifi-
cation, the HUB Repeater provides the following functions:
Transaction Translator
The Transaction Translator (TT) basically translates data from
one speed to another. A TT takes high-speed split transactions
and translates them to full-/low-speed transactions when the
hub is operating at high speed (the upstream port is connected
to a high-speed host controller) and has full-/low-speed
devices attached. The operating speed of a device attached
on a downstream facing port determines whether the Routing
Logic connects a port to the Transaction Translator or Hub
Repeater. If a full-/low-speed device is connected to the hub
operating at high speed, the data transfer route includes the
Transaction Translator. If a high-speed device is connected to
this high-speed hub, the route only includes the repeater and
no Transaction Translator since the device and the hub are
operating at the same speed. When the hub is operating at full
speed (the upstream port is connected to a full-speed host
controller), a high-speed peripheral does not operate at its full
capability. These devices only work at full speed. Full- and
low-speed devices connected to this hub operate at their
normal speed.
Applications
Typical applications for the HX2LP device family are:
Functional Overview
The Cypress CY7C656xx USB 2.0 Hubs are high perfor-
mance, low system cost solutions for USB. The CY7C656xx
USB 2.0 Hubs integrate 1.5 k
full-speed operation and all downstream 15 k
resistors as well as series termination resistors on all upstream
and downstream D+ and D– pins. This results in optimization
of system costs by providing built-in support for the USB 2.0
specification.
• Sets up and tears down connectivity on packet boundaries
• Ensures orderly entry into and out of the Suspend state,
• Standalone hubs
• Motherboard hubs
• Monitor hubs
• Advanced port replicators
• Docking stations
• Split-PC designs
• External personal storage drives
• Keyboard hubs
including proper handling of remote wakeups.
Ω
upstream pull up resistors for
Ω
pull down
System Initialization
On power up, the CY7C656xx reads an external SPI EEPROM
for configuration information. At the most basic level, this
EEPROM has the Vendor ID (VID), Product ID (PID), and
Device ID (DID) for the customer's application. For more
specialized applications, other configuration options can be
specified. See
details.
After reading the EEPROM, if VBUSPOWER (connected to
up-stream V
resistor on D+ to indicate its presence to the upstream hub,
after which a USB Bus Reset is expected. During this reset,
CY7C656xx initiates a chirp to indicate that it is a high-speed
peripheral. In a USB 2.0 system, the upstream hub responds
with a chirp sequence, and CY7C656xx is in a high-speed
mode, with the upstream D+ pull up resistor turned off. In
USB 1.x systems, no such chirp sequence from the upstream
hub is seen, and CY7C656xx operates as a normal 1.x hub
(operating at full speed).
Enumeration
After a USB Bus Reset, CY7C656xx is in an unaddressed,
unconfigured state (configuration value set to ’0’). During the
enumeration process, the host sets the hub's address and
configuration.
Once the hub is configured, the full hub functionality is
available.
Downstream Ports
The CY7C656xx supports a maximum of four downstream
ports, each of which may be marked as usable or removable
in the extended configuration (0xD2 EEPROM load or 0xD4
EEPROM load, see
Downstream D+ and D– pull down resistors are incorporated
in CY7C656xx for each port. Before the hubs are configured,
the ports are driven SE0 (Single Ended Zero, where both D+
and D– are driven low) and are set to the unpowered state.
Once the hub is configured, the ports are not driven, and the
host may power the ports by sending a SetPortPower
command for each port. After a port is powered, any connect
or disconnect event is detected by the hub. Any change in the
port state is reported by the hubs back to the host through the
Status Change Endpoint (endpoint 1). Upon receipt of
SetPortReset request for a port with a device connected, the
hub does as follows:
Babble consists of a non-idle condition on the port after EOF2.
If babble is detected on an enabled port, that port is disabled.
A ClearPortEnable request from the host also disables the
specified port.
Downstream ports can be individually suspended by the host
with the SetPortSuspend request. If the hub is not suspended,
a remote wakeup event on that port is reflected to the host
through a port change indication in the Hub Status Change
Endpoint. If the hub is suspended, a remote wakeup event on
• Performs a USB Reset on the corresponding port
• Puts the port in an enabled state
• Enables the green port indicator for that port (if not previ-
• Enables babble detection once the port is enabled.
ously overridden by the host)
BUS
“Configuration Options” on page 11
) is high, CY7C656xx enables the pull up
“Configuration Options” on page
CY7C656xx
Page 3 of 24
for more
11.
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