Lattice Semiconductor
Application Support
IPUG39_02.9, December 2010
29
10 Gb+ Ethernet MAC IP Core User’s Guide
Maximum Packet Size (MAX_PKT_LEN)
This register should be overwritten only when the MAC is disabled. All frames longer than the value (number of
bytes) in this register will be tagged as long frames. Writing this register while the MAC is active results in unpre-
dictable behavior.
Table 5-6. Maximum Packet Size Register Description
IPG Value (IPG_VAL)
This register contains the IPG value to be used by the TX MAC. Back to back packets in the transmit buffer will be
sent out with the IPG setting programmed in this register.
Table 5-7. IPG Value Register Description
MAC Address Register {0,1,2,3,4,5}, Set of six (MAC_ADDR_[5-0])
Note that the MAC address is stored in the registers in Hexadecimal form, so for example to set the MAC Address
to: AC-DE-48-00-00-80 would require writing 0xAC (octet 0) to address 0x07, 0xDE (octet 1) to address 0x08, 0x48
(octet 2) to address 0x09, 0x00 (octet 3) to address 0x0A, 0x00 (octet 4) to address 0x0B, and 0x80 (octet 5) to
address 0x0C.
Table 5-8. MAC Address Register Description
Name: MAX_PKT_SIZE
Address: A04H
Bits
Name
Type
Default
Description
7:6
UNUSED
—
—
Reserved
5:0
Max_frame_0
R/W
05H
Maximum Frame Length. Used only for statistical purposes, all
frames longer than the value given here will be marked as long.
This value will in not manner affect the frame’s reception. Upper
byte.
Name: MAX_PKT_SIZE
Address: A05H
Bits
Name
Type
Default
Description
7:0
Max_frame_1
R/W
EEH
Maximum Frame Length. Used only for statistical purposes, all
frames longer than the value given here will be marked as long.
This value will in not manner affect the frame's reception. Lower
byte.
Name: IPG_VAL
Address: A06H
Bits
Name
Type
Default
Description
7:5
UNUSED
—
—
Reserved
4:0
IPG_Value
R/W
01H
Transmit Inter Packet Gap. Specifies the amount of inter-frame
gap in increments of 4 bytes. Value of 0 indicates the minimum
value of 8 bytes.
Name: MAC_ADDR
Address: A07H, A08H, A09H, A0AH, A0BH, A0CH
Bits
Name
Type
Default
Description
7:0
Mac_Addr[0-5]
R/W
0
MAC Address. Ethernet address assigned to the port supported
by the MAC.
