Maxim Integrated 78Q8430 Software Driver - Manual (Page 22)

78Q8430 Software Driver Development Guidelines UG_8430_004
STEP 2: Write pattern and mask byte [1] through byte [4] to the CAM.
For each byte, CAM rule 0x15-N, where N is the byte number, is written as follows:
Reg. Field Value to write
byte [1]: byte [2]: byte [3]: byte [4]: CAR ADDR
0x14 0x13 0x12 0x11
Data Match Pattern byte [1] … byte [4]
Data Mask 0x00 to mask, else 0xFF
Previous Hit Match Value of the CAM rule used by the previous byte
1
RMR
Previous Hit Mask 0x7F
Byte Offset Retain default: 0x00
Interrupt Retain default: 0
Control Logic Action Retain default: NOP
RCR
Match Control Retain default: MD
1
The Previous Hit Match fields for byte [1] through byte [4] are 0x15, 0x14, 0x13 and 0x12.
STEP 3: Write address and mask byte [5] to the CAM.
Write CAM rule 0x10 as follows.
Reg. Field Value to write
CAR ADDR 0x10
Data Match Pattern byte [5]
Data Mask 0x00 to mask, else 0xFF
Previous Hit Match Set to the CAM rule that was used for byte [4] (0x11).
RMR
Previous Hit Mask 0x7F
Byte Offset Retain default: 0x00
Interrupt Retain default: 0
Control Logic Action Retain default: WAKE
RCR
Match Control Retain default: DONE
STEP 4: Enable OnNow.
STEP 1 of this procedure disabled the OnNow feature. Modify CAM rule 0x15 to enable the filter.
• Set the CAR Address field to 0x15.
• Set the RMR Previous Hit Mask field to 0x7F.
It is important that STEP 1 disable the OnNow feature while the pattern is being set so that no
frames are matched against a partial pattern before the entire pattern is set.
The existing rules will only match the OnNow pattern starting with the first byte of the IP payload. In some
cases it may be desirable for the OnNow pattern to match an ARP request or other standard frame. In
this case, it may be possible to leverage other rules to accomplish this with only a few rules. This cannot
be done by the procedure specified here.
4.4 Magic Packet Recognition
Identifying a Magic Packet frame is based on matching a specific sequence of bytes based on the MAC
address of the target. CAM rules 0x0F down through 0x02 are reserved for Magic Packet recognition.
Rules 0x0F, 0x0E and 0x0D can all be entry points for the Magic Packet rules. If rules 0x0F, 0x0E and
0x0D are all disabled, the CAM no longer identifies Magic Packets.
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