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Renesas Electronics America - Knowledgebase

What causes a rise of value in the delayed collision CDCR of the EtherC?

Latest Updated:03/21/2012


What causes an increment of the value in the delayed collision detect counter register (CDCR) of the ethernet controler (EtherC)?


A collision in the ethernet usually occurs during the transmission of  the first 64 bytes (512 bits) in the frame.
If a collision occurs during this 512-bit time transmission, the collision becomes a delayed collision which invites an increment in CDCR.

There may be some causes for a delayed collision. One of them can be a mismatch of the full-duplex settings between the edges of the link on the improper network configuration that does not comply with the specification. An excessive signal crosstalk between the twisted pair lines, and a damaged hardware may also cause a delayed collision.

Suitable Products
SH7214, SH7216