Functional Description
Notes for the Tx Statistics Summary:
1. "AND" is assumed horizontally across the table between all conditions which form the statistic (marked
y or n) except where (y|y), meaning “OR” is indicated. Parentheses are significant.
2. “-“ indicates conditions which are ignored in the formations of the statistic.
3. Statistics marked “Rx+Tx” are formed by summing the Rx and Tx statistics, each of which is formed
independently.
4. Pause (MAC) frames are issued in the MAC as perfect (no CRC error) 64 byte frames in full duplex
only, so they cannot collide.
5. “%” If a CPU sourced MAC control frame has a multicast or broadcast destination address then the
appropriate statistics will be updated.
6. “+” indicates collisions which are “summed” (i.e. every collision is counted in the Collisions statistic).
Jam sequences used for halfduplex flow control are also counted.
7. “$” Every byte written on the wire during each retry attempt is also counted in addition to frames which
experience no collisions or carrier loss.
8. The flow collision type is for half-duplex collisions forced by the MAC to achieve flow control. Some of
the ‘-‘s in this column might in reality be ‘n’s. To prevent double-counting, Net Octets are unaffected by
the jam sequence – the ‘received’ bytes, however, are counted. (See
9. When the transmit Tx FIFO is drained due to the MAC being disabled or link being lost, then the
frames being purged will not appear in the Tx statistics.
1222
Ethernet Subsystem
SPRUH73H – October 2011 – Revised April 2013
Copyright © 2011–2013, Texas Instruments Incorporated