Artesyn COMX-P1022 Installation and Use (July 2014) - Manual (Page 63)

Functional Description
COMX-P1022 COM Express Module Installation and Use (6806800M04C) 63
4.6.6 USB Hub
There is one USB2514 located on I2C#2, and the device address is 0x58.
USB2514 is a USB hub controller IC with 4 downstream ports for embedded USB solutions. The
4-port hub is fully compliant with the USB 2.0 Specification and will attach to an upstream port
as a Full-Speed Hub or as a Full-/High-Speed Hub, and High Speed (if operating as a High-Speed
Hub) downstream devices on all of the enabled downstream ports.
The SMSC Hub must be configured in order to correctly function when attached to a USB host
controller. There are three principal ways to configure the hub: SMBus, EEPROM, or by internal
default setting. In all cases, the configuration method will be determined by the CFG_SEL2,
CFG_SEL1 and CFG_SEL0 pins immediately after RESET_N negation.
In SMBus case, the CFG_SEL1 and CFG_SEL0 pins must be 01, so the Hub can be configured as
an SMBus slave for external download of user-defined descriptors.
The USB Hub can work well even without any configuration. So U-boot doesn't need to access
the USB Hub registers through I2C bus unless special requirements are need.
4.6.7 PCA9545
The PCA9545 is a quad bi-directional translating switch controlled via the I2C bus. The SCL/SDA
upstream pair fans out to four downstream pairs, or channels. Any individual SCx/SDx channel
or combination of channels can be selected, determined by the contents of the programmable
control register. Four interrupt inputs, INT0 to INT3, one for each of the downstream pairs, are
provided, but in this case, they are not used.