Network Card User Manual

Ethernet Media Access Controller (EMAC) Registers www.ti.com
5.24 Receive Maximum Length Register (RXMAXLEN)
The receive maximum length register (RXMAXLEN) is shown in Figure 63 and described in Table 61.
Figure 63. Receive Maximum Length Register (RXMAXLEN)
31 16
Reserved
R-0
15 0
RXMAXLEN
R/W-1518
LEGEND: R = Read only; R/W = Read/Write; -n = value after reset
Table 61. Receive Maximum Length Register (RXMAXLEN) Field Descriptions
Bit Field Value Description
31-16 Reserved 0 Reserved
15-0 RXMAXLEN 0-FFFFh Receive maximum frame length. These bits determine the maximum length of a received frame.
The reset value is 5EEh (1518). Frames with byte counts greater than RXMAXLEN are long
frames. Long frames with no errors are oversized frames. Long frames with CRC, code, or
alignment error are jabber frames.
5.25 Receive Buffer Offset Register (RXBUFFEROFFSET)
The receive buffer offset register (RXBUFFEROFFSET) is shown in Figure 64 and described in
Table 62.
Figure 64. Receive Buffer Offset Register (RXBUFFEROFFSET)
31 16
Reserved
R-0
15 0
RXBUFFEROFFSET
R/W-0
LEGEND: R = Read only; R/W = Read/Write; -n = value after reset
Table 62. Receive Buffer Offset Register (RXBUFFEROFFSET) Field Descriptions
Bit Field Value Description
31-16 Reserved 0 Reserved
15-0 RXBUFFEROFFSET 0-FFFFh Receive buffer offset value. These bits are written by the EMAC into each frame SOP
buffer descriptor Buffer Offset field. The frame data begins after the RXBUFFEROFFSET
value of bytes. A value of 0 indicates that there are no unused bytes at the beginning of
the data, and that valid data begins on the first byte of the buffer. A value of Fh (15)
indicates that the first 15 bytes of the buffer are to be ignored by the EMAC and that valid
buffer data starts on byte 16 of the buffer. This value is used for all channels.
106
Ethernet Media Access Controller (EMAC)/Management Data Input/Output SPRUFI5B–March 2009–Revised December 2010
(MDIO)
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