Processor Users Manual

MOTOROLA Chapter 30. Fast Ethernet Controller 30-11
Part IV. Communications Processor Module
0xBA MAXD2 Hword Max DMA2 length register (typically 1520 decimal). Lets the user prevent system bus
writes after a frame exceeds a speciÞed size. The value of MAXD2 is valid in
promiscuous mode when no address match is detected. If the Ethernet controller
detects an incoming Ethernet frame larger than the value in MAXD2, the rest of the
frame is discarded. The Ethernet controller waits for the end of the frame (or until
MFLR bytes are received) and reports frame status and length (including the
discarded bytes) in the last RxBD. In a monitor station, MAXD2 can be much less
than MAXD1 to receive entire frames addressed to this station, but receive only the
headers of all other frames.This value must be less than MAXD1.
0xBC MAXD Hword Rx maximum DMA. Internal usage
0xBE DMA_CNT Hword Rx DMA counter. Temporary down-counter used to track the frame length.
0xC0 OCTC
2
Word (RMON mode only) The total number of octets of data (including those in bad
packets) received on the network (excluding framing bits but including FCS octets).
0xC4 COLC
2
Word (RMON mode only) The best estimate of the total number of collisions on this
Ethernet segment.
0xC8 BROC
2
Word (RMON mode only) The total number of good packets received that were directed to
the broadcast address. Note that this does not include multicast packets.
0xCC MULC
2
Word (RMON mode only) The total number of good packets received that were directed to
a multicast address. Note that this number does not include packets directed to the
broadcast address.
0xD0 USPC
2
Word (RMON mode only) The total number of packets received that were less than 64
octets (excluding framing bits but including FCS octets) and were otherwise well-
formed.
0xD4 FRGC
2
Word (RMON mode only) The total number of packets received that were less than 64
octets long (excluding framing bits but including FCS octets) and had either a bad
FCS with an integral number of octets (FCS error) or a bad FCS with a non-integral
number of octets (alignment error). Note that it is entirely normal for
etherStatsFragments to increment because it counts both runts (which are normal
occurrences due to collisions) and noise hits.
0xD8 OSPC
2
Word (RMON mode only) The total number of packets received that were longer than 1518
octets (excluding framing bits but including FCS octets) and were otherwise well-
formed.
0xDC JBRC
2
Word (RMON mode only) The total number of packets received that were longer than 1518
octets (excluding framing bits but including FCS octets), and had either a bad FCS
with an integral number of octets (FCS error) or a bad FCS with a non-integral
number of octets (alignment error). Note that this deÞnition of jabber is different than
the deÞnition in IEEE-802.3 section 8.2.1.5 (10BASE5) and section 10.3.1.4
(10BASE2). These documents deÞne jabber as the condition where any packet
exceeds 20 ms. The allowed range to detect jabber is between 20 ms and 150 ms.
0xE0 P64C
2
Word (RMON mode only) The total number of packets (including bad packets) received
that were 64 octets long (excluding framing bits but including FCS octets).
0xE4 P65C
2
Word (RMON mode only) The total number of packets (including bad packets) received
that were between 65 and 127 octets long inclusive (excluding framing bits but
including FCS octets).
Table 30-2. Ethernet-Specific Parameter RAM (Continued)
Offset
1
Name Width Description