
CY7C65640
Document #: 38-08019 Rev. *E
Page 7 of 27
2.3
The Hub Control Block does the following protocol handling at a higher level:
Coordinate enumeration by responding to SETUP packets
Fill and empty the FIFOs
Suspend/Resume coordination
Verify and select DATA toggle values
Port power control and over-current detection.
The Hub Controller provides status and control and permits host access to the hub.
Hub Controller
2.4
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. Per the USB 2.0 specification, the Hub Repeater
provides the following functions:
Sets up and tears down connectivity on packet boundaries
Ensures orderly entry into and out of the Suspend state, including proper handling of remote wakeups.
Hub Repeater
2.5
The 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 section. If a low-/full-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 in conformation with respect to their data transfer speed. When the hub is operating at full speed (the upstream
port is connected to a full-speed host controller), a high-speed peripheral will not operate at its full capability. These devices will
only work at 1.1 speed. Full- and low-speed devices connected to this hub will operate at their 1.1 speed.
Transaction Translator
3.0
Applications
Standalone Hubs
Motherboard Hubs
Monitor Hub applications
External Personal Storage Drives
Port Replicators
Portable Drive
Docking Stations
4.0
Functional Overview
The Cypress TetraHub USB 2.0 Hub is a high-performance, low-system-cost solution for USB. The TetraHub USB 2.0 Hub
integrates 1.5k upstream pull-up resistors for full-speed operation and all downstream 15k pull-down 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.
4.1
On power-up, the TetraHub will read an external SPI EEPROM for configuration information. At the most basic level, this EEPROM
will have 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 section 8.0 for more details.
After reading the EEPROM, if BUSPOWER (connected to up-stream VBus) is HIGH, TetraHub will enable the pull-up resistor on
the D+ to indicate that it is connected to the upstream hub, after which a USB Bus Reset is expected. During this reset, TetraHub
will initiate a chirp to indicate that it is a high-speed peripheral. In a USB 2.0 system, the upstream hub will respond with a chirp
sequence, and TetraHub will be 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 will be seen, and TetraHub will operate as a normal 1.x hub (operating at full speed).
System Initialization
4.2
After a USB Bus Reset, TetraHub is in an unaddressed, unconfigured state (configuration value set to 0). During the enumeration
process, the host will set the hub's address and configuration by sending a SetCongfiguration request. Changing the hub address
will restore it to an unconfigured state.
Enumeration