Method and apparatus for temporal alignment of multiple parallel data streams

A method of aligning data streams output by two or more bidirectional ports of a circuit, comprising:

• looping-back a test pattern via a first transmitter and a receiver associated with a second transmitter to a receive buffer;
• storing the contents of the receive buffer;
• looping-back the test pattern via the second transmitter and the receiver to the receive buffer;
• comparing the contents of the receive buffer with the stored previous contents of the receive buffer so that if the contents are the same, a determination is made that the first and second transmitters are in alignment, and if the contents are not the same, determining a misalignment between the first and second transmitters and shifting a data stream output by at least one of the first and second transmitters in accordance with the misalignment so as to offset the misalignment.

A method of aligning data streams output by two or more bidirectional ports of a circuit, comprising:

• determining a receive path misalignment between a first receiver associated with a first transmitter of a first port and a second receiver associated with a second transmitter of a second port;
• determining a combined path misalignment between the first port and the second port by:
• looping-back a test pattern via the first transmitter and the first receiver to a first receive buffer,
• looping-back the test pattern via the second transmitter and the second receiver to a second receive buffer, and
• comparing the contents of the first and second receive buffers;
• determining a transmit path misalignment between the first transmitter and the second transmitter as a function of the combined path misalignment and the receive path misalignment;
• and
• shifting a data stream output by at least one of the first and second transmitters in accordance with the transmit path misalignment so as to offset the transmit path misalignment.