Intel C2550 FH8065401488912 Data Sheet

Intel

®

 Atom™ Processor C2000 Product Family for Microserver

September 2014

Datasheet, Vol. 2 of 3

Order Number: 330061-002US

281

Two mutually exclusive conditions that the debug software must address as part of its 

startup processing are:

• The EHCI has been initialized by the system software.
• The EHCI has not been initialized by the system software.

The debug software determines the current initialized state of the EHCI by examining 

the configure flag in the EHCI USB 2.0 Command register. If this flag is set, then the 

system software has initialized the EHCI. Otherwise, the EHCI is not considered 

initialized. The debug software initializes the debug port registers depending on the 

state the EHCI. However, before this is accomplished, the debug software must 

determine which root USB port is designated as the debug port.

The debug software easily determines which USB root port has been designated as the 

debug port by examining bits [20:23] of the EHCI Host Controller Structural 

Parameters register. For the SoC, this 4-bit field is hardwired as 2h indicating that the 

Debug Port is on the second port on the EHC which is Port #1.