78Q8430-128CGT/F Maxim Integrated Products, 78Q8430-128CGT/F Datasheet - Page 39

• Manufacturer Part Number: 78Q8430-128CGT/F
• Description: Telecom ICs 10/100MAC+PHY MULTI MEDIA OFFLOAD CNTRLR
• Manufacturer: Maxim Integrated Products

DS_8430_001
RCR Match Control
The value of the Match Control field will determine how the control logic generates the next CAM
reference word.
6.7.3
The following table shows the format of an Ethernet frame. The fields are in the order that the
classification engine sees them, from left to right. The byte count for each field is specified on the bottom
row of the table.
If the Len/Type field contains a 16-bit value that is less than 0x0600, the field is interpreted as a length
field that specifies the number of bytes in the User field. If the value is greater than or equal to 0x0600,
the type interpretation is to be used.
6.7.4
This section provides the default rules that the 78Q8430B CAM is loaded with on reset.
Rev. 1.2
Hex
Value
0x14
0x15
0x16
0x17
0x18
0x1A
0x1B
0x1C
0x1D
0x1E
0x1F
Value
00b
10b
01b
11b
Destination
Address
6 Bytes
Frame Format
Binary
Value
10100b
10101b
10110b
10111b
11000b
11010b
11011b
11100b
11101b
11110b
11111b
Default CAM Rule Summary
Name
DONE
MD
MX
DROP
Source
Address
6 Bytes
Name
THXA
SETMC
VLAN
SETBC
TOC
DEC
MCTL
TDPH
TDLTH
TDPL
TDLTL
No more CAM reference words are generated. No further classification is
done for the current frame.
The next frame data is used to generate the next CAM reference word.
The ‘X’ value is used in place of the frame data to generate the next CAM
reference word.
Drop the frame. If this is executed within the first 128 bytes of the frame
then the entire frame is dropped from the QUE. No more CAM reference
words are generated.
Table 28: Ethernet Frame for Classification
The high-order nibble of the classification result is assigned the value of
the high-order nibble value of ‘X’.
Mark the frame as multicast for Rx statistics purposes.
Mark the frame as VLAN tagged for length checking and statistics.
Mark the frame as broadcast for Rx statistics purposes.
The control logic counter value is initialized to the value contained in the
Byte Offset field. No offset is applied.
The control logic counter value is decremented. If the counter has
reached zero then the control logic will decrement the previous hit value
used to generate the next CAM reference word by one.
Classify the frame as a MAC control frame. This also sets the Len/Type
LSB.
The pause counter most significant byte is set from the frame data.
The Len/Type most significant byte is set from the frame data.
The pause counter least significant byte is set from the frame data.
The Len/Type least significant byte is set from the frame data.
1B
Hi
Len/Typ
Table 27: RCR Match Control
1B
Lo
0-1500B
User
LLC Data
Action Taken
46-0B
Action Taken
Pad
MSB
CRC (FCS)
4 Bytes
78Q8430 Data Sheet
LSB
39