Robust and scalable de-skew method for data path skew control
View Patent ↗A method for selectively deskewing data traveling through a bus in a network device is disclosed. Bit-level data is received from each data line of a plurality of data lines of the bus. Vertical line information is detected for the plurality of data lines to determine if there is a match with a training pattern. A skew distance is calculated once there is a match with the training pattern. Then, the plurality of data lines are bit aligned based on the skew distance.
1. A method for selectively deskewing data traveling through a bus in a network device, comprising:
receiving bit-level data from each data line of a plurality of data lines of said bus;
detecting vertical line information for the plurality of data lines to determine if there is a match with a training pattern;
calculating a skew distance once there is said match with the training pattern; and
bit aligning the plurality of data lines based on the skew distance.
2. The method according to claim 1 , wherein said method is capable of deskewing data having a skew distance up to a 5-bit distance.
3. The method according to claim 1 , wherein said step of receiving bit-level data comprises receiving bit-level data sent via a system packet interface level 4 interface.
4. The method according to claim 1 , further comprising checking a manual skew register to determine if a manual deskew process should be performed.
5. The method according to claim 4 , wherein when the manual skew register indicates that the manual deskew process should be performed, the step of bit aligning the plurality of data lines occurs according to a manual skew distance entered by a user.
6. The method according to claim 1 , further comprising checking a freeze current deskew pattern register to determine if a current deskew pattern should be maintained.
7. The method according to claim 6 , wherein when the freeze current deskew pattern register indicates that the current deskew pattern should be maintained, the step of calculating a skew distance comprises setting the skew distance based the current skew pattern.
8. An apparatus for selectively deskewing data traveling through a bus in a network device, comprising:
means for receiving bit-level data from each data line of a plurality of data lines of said bus;
means for detecting vertical line information for the plurality of data lines to determine if there is a match with a training pattern;
means for calculating a skew distance once there is said match with the training pattern; and
means for bit aligning the plurality of data lines based on the skew distance.
9. The apparatus according to claim 8 , wherein said apparatus is capable of deskewing data having a skew distance up to a 5-bit distance.
10. The apparatus according to claim 8 , wherein said means for receiving bit-level data comprises means for receiving bit-level data sent via a system packet interface level 4 interface.
11. The apparatus according to claim 8 , further comprising means for checking a manual skew register to determine if a manual deskew process is selected.
12. The apparatus according to claim 11 , wherein when the manual deskew process is selected, the means for bit aligning the plurality of data lines is configured to use the manual skew distance entered by a user.
13. The apparatus according to claim 8 , further comprising means for checking a freeze current deskew pattern register to determine if a current deskew pattern should be maintained.
14. The apparatus according to claim 13 , wherein when the freeze current deskew pattern register indicates that the current deskew pattern should be maintained, the means for calculating a skew distance comprises means for setting the skew distance based the current skew pattern.