LAN9311 Datasheet, PDF (341/461 Pages) SMSC Corporation – Two Port 10/100 Managed Ethernet Switch with 16-Bit Non-PCI CPU Interface

Two Port 10/100 Managed Ethernet Switch with 16-Bit Non-PCI CPU Interface
Datasheet
14.5.2.18 Port x MAC Receive Alignment Error Count Register (MAC_RX_ALIGN_CNT_x)
Register #:
Port0: 041Fh
Port1: 081Fh
Port2: 0C1Fh
Size:
32 bits
This register provides a counter of received packets with 64 bytes to the maximum allowable, and a
FCS error. The counter is cleared upon being read.
BITS
31:0
DESCRIPTION
RX Alignment
Count of packets that have between 64 bytes and the maximum allowable
number of bytes and are not byte aligned and have a bad FCS. The max
number of bytes is 1518 for untagged packets and 1522 for tagged packets.
If Jumbo2K (bit 3) is set in the Port x MAC Receive Configuration Register
(MAC_RX_CFG_x), the max number of bytes is 2048.
Note: This counter will stop at its maximum value of FFFF_FFFFh.
Minimum rollover time at 100Mbps is approximately 481 hours.
TYPE
RC
DEFAULT
00000000h
Note: For this counter, a packet with the maximum number of bytes that is not an integral number of
bytes (e.g. a 1518 1/2 byte packet) and a FCS error is considered an alignment error and is
counted.
SMSC LAN9311/LAN9311i
341
DATASHEET
Revision 2.0 (02-14-13)