Ethernet Media Access Controller (EMAC)/ Management Data Input/Output (MDIO) Module User's Guide

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5.50.16 Multicast Transmit Frames Register (TXMCASTFRAMES)
5.50.17 Pause Transmit Frames Register (TXPAUSEFRAMES)
5.50.18 Deferred Transmit Frames Register (TXDEFERRED)
5.50.19 Transmit Collision Frames Register (TXCOLLISION)
5.50.20 Transmit Single Collision Frames Register (TXSINGLECOLL)
Ethernet Media Access Controller (EMAC) Registers
The total number of good multicast frames transmitted on the EMAC. A good multicast frame is defined
as having all of the following:
• Any data or MAC control frame destined for any multicast address other than FF-FF-FF-FF-FF-FFh
• Was of any length
• Had no late or excessive collisions, no carrier loss, and no underrun
The total number of IEEE 802.3X pause frames transmitted by the EMAC. Pause frames cannot
underrun or contain a CRC error because they are created in the transmitting MAC, so these error
conditions have no effect on this statistic. Pause frames sent by software are not included in this count.
Since pause frames are only transmitted in full-duplex mode, carrier loss and collisions have no effect
on this statistic.
Transmitted pause frames are always 64-byte multicast frames so appear in the multicast transmit
frames register and 64 octet frames register statistics.
The total number of frames transmitted on the EMAC that first experienced deferment. Such a frame is
defined as having all of the following:
• Was any data or MAC control frame destined for any unicast, broadcast, or multicast address
• Was any size
• Had no carrier loss and no underrun
• Experienced no collisions before being successfully transmitted
• Found the medium busy when transmission was first attempted, so had to wait.
CRC errors have no effect on this statistic.
The total number of times that the EMAC experienced a collision. Collisions occur under two
circumstances:
• When a transmit data or MAC control frame has all of the following:
– Was destined for any unicast, broadcast, or multicast address
– Was any size
– Had no carrier loss and no underrun
– Experienced a collision. A jam sequence is sent for every non-late collision, so this statistic
increments on each occasion if a frame experiences multiple collisions (and increments on late
collisions).
• When the EMAC is in half-duplex mode, flow control is active, and a frame reception begins.
CRC errors have no effect on this statistic.
The total number of frames transmitted on the EMAC that experienced exactly one collision. Such a
frame is defined as having all of the following:
• Was any data or MAC control frame destined for any unicast, broadcast, or multicast address
• Was any size
• Had no carrier loss and no underrun
• Experienced one collision before successful transmission. The collision was not late.
128 Ethernet Media Access Controller (EMAC)/Management Data Input/Output (MDIO) SPRUEQ6 – December 2007
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