Section 14.5.2.19, Datasheet – SMSC LAN9312 User Manual

Page 340

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High Performance Two Port 10/100 Managed Ethernet Switch with 32-Bit Non-PCI CPU Interface

Datasheet

Revision 1.4 (08-19-08)

340

SMSC LAN9312

DATASHEET

14.5.2.19

Port x MAC Receive Packet Length Count Register (MAC_RX_PKTLEN_CNT_x)

This register provides a counter of total bytes received. The counter is cleared upon being read.

Note:

If necessary, for oversized packets, the packet is either truncated at 1518 bytes (untagged,
Jumbo2K=0), 1522 bytes (tagged, Jumbo2K=0), or 2048 bytes (Jumbo2K=1). If this occurs,
the byte count recorded is 1518, 1522, or 2048, respectively. The Jumbo2K bit is located in
the

Port x MAC Receive Configuration Register (MAC_RX_CFG_x)

.

Note:

A bad packet is one that has an FCS or Symbol error. For this counter, a packet that is not an
integral number of bytes (e.g. a 1518 1/2 byte packet) is rounded down to the nearest byte.

Register #:

Port0: 0420h

Size:

32 bits

Port1: 0820h
Port2: 0C20h

BITS

DESCRIPTION

TYPE

DEFAULT

31:0

RX Bytes
Count of total bytes received (including bad packets).

Note:

This counter will stop at its maximum value of FFFF_FFFFh.
Minimum rollover time at 100Mbps is approximately 5.8 hours.

RC

00000000h

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