High Performance Two Port 10/100 Managed Ethernet Switch with 32-Bit Non-PCI CPU Interface
Datasheet
"Flow Control Enable Logic," on page 58. Pause frames are consumed by the MAC and not sent to
the switch engine. Non-pause control frames are optionally filtered or forwarded.
When the receive FIFO is full and additional data continues to be received, an overrun condition occurs
and the frame is discarded (FIFO space recovered) or marked as a bad frame.
The receive MAC can be disabled from receiving all frames by clearing the RX Enable bit of the Port
x MAC Receive Configuration Register (MAC_RX_CFG_x).
The size of the RX FIFO is 256 bytes. If a bad packet with less than 64 bytes is received, it will be
flushed from the FIFO automatically and the FIFO space recovered. Packets equal to or larger than
64 bytes with an error will be marked and reported to the switch engine. The switch engine will
subsequently drop the packet.
6.3.1.1
Receive Counters
The receive MAC gathers statistics on each packet and increments the related counter registers. The
following receive counters are supported for each switch fabric port. Refer to Table 14.12, “Indirectly
Accessible Switch Control and Status Registers,” on page 308 and Section 14.5.2.3 through
Section 14.5.2.22 for detailed descriptions of these counters.
Total undersized packets (Section 14.5.2.3, on page 325)
Total packets 64 bytes in size (Section 14.5.2.4, on page 326)
Total packets 65 through 127 bytes in size (Section 14.5.2.5, on page 327)
Total packets 128 through 255 bytes in size (Section 14.5.2.6, on page 328)
Total packets 256 through 511 bytes in size (Section 14.5.2.7, on page 329)
Total packets 512 through 1023 bytes in size (Section 14.5.2.8, on page 330)
Total packets 1024 through maximum bytes in size (Section 14.5.2.9, on page 331)
Total oversized packets (Section 14.5.2.10, on page 332)
Total OK packets (Section 14.5.2.11, on page 333)
Total packets with CRC errors (Section 14.5.2.12, on page 334)
Total multicast packets (Section 14.5.2.13, on page 335)
Total broadcast packets (Section 14.5.2.14, on page 336)
Total MAC Pause packets (Section 14.5.2.15, on page 337)
Total fragment packets (Section 14.5.2.16, on page 338)
Total jabber packets (Section 14.5.2.17, on page 339)
Total alignment errors (Section 14.5.2.18, on page 340)
Total bytes received from all packets (Section 14.5.2.19, on page 341)
Total bytes received from good packets (Section 14.5.2.20, on page 342)
Total packets with a symbol error (Section 14.5.2.21, on page 343)
Total MAC control packets (Section 14.5.2.22, on page 344)
SMSC LAN9312
Revision 1.2 (04-08-08)
DATA6S1HEET
SMSC [ SMSC CORPORATION ]
