Type: Answers

Area: Intellectual Property


IP Product: Triple Speed Ethernet MAC

Why does the Triple Speed Ethernet LINK_STATUS bit change value if read twice?

Description

The Triple Speed Ethernet (TSE) user guide (refer to Table 5-9) states that if link synchronization is lost, the LINK_STATUS bit is latched to 0.  This value remains unchanged, even if the link re-synchronizes and will only be updated once the user reads the LINK_STATUS bit.

This is expected behaviour, and is seen in all supported device families.  The reason for implementing this feature is to ensure the IP informs the user that link synchronization was lost even if the link is restored before the status is read.