Programmer’s Guide BCM5722
10/15/07
Broadcom Corporation
Document 5722-PG101-R Wake on LAN Mode/Low-Power Page 160
OPERATIONAL CHARACTERISTICS
Internal Memory
The WOL pattern must be stored in the BCM5722 Ethernet controller miscellaneous memory region. All memory locations
require the host software to reinitialize the WOL pattern before each D0 to D3 transition. The RX/TX MAC places packets
into this internal memory and the WOL pattern is overwritten during normal operation. When the BCM5722 Ethernet control-
ler operates in D0 state, internal data structures use the same memory location as the WOL pattern. Host software should
re-initialize the WOL pattern before each WOL sleep transition.
Table 75 shows the required memory regions for the WOL pattern.
WOL Pattern Pointer Register
The WOL_Pattern_Pointer specifies a location within BCM5722 Ethernet controller address space where the pattern buffers
reside (see “WOL Pattern Pointer Register (Offset 0x430)” on page 249 for the register definition). The internal memory sub-
section discusses how host programmers can choose an address range. The WOL_Pattern_Pointer register uses a pointer
value, not an internal memory location. The pointer value is calculated by dividing an internal memory location by the value
8. Do not program the WOL_Pattern_Pointer register with the actual internal memory location. Rather, host software must
first convert the base address to a pointer value. Here are example conversion from memory base to pointer values:
• 0x0000 (Misc Memory)/8 = 0x00 (required value)
• 0x400 (base addr)/8 = 0x80 (pointer value)
• 0x8000 (base addr)/8 = 0x1000 (pointer value)
• 0xF000 (base addr)/8 = 0x1E00 (pointer value)
WOL Pattern Configuration Register
The WOL_Pattern_Configuration register contains two programmable data fields. Both fields use different units of measure-
ment, so the host programmer should be careful (see “WOL Pattern Configuration Register (Offset 0x434)” on page 250 for
the register definition). This register is used to position and extract data from RX Ethernet frames.
• Offset Field—The Offset field in the WOL_Pattern_Configuration register specifies a position in RX Ethernet frame(s),
where comparisons for WOL patterns should begin. This register uses a unit of measurement specified in terms of 2-
byte chunks. Software should not program this field with a byte value, but should first normalize to a 2-byte unit.
Hardware cannot begin WOL comparisons on odd byte alignments (i.e., 3,5,7,9 offsets). Host software must begin all
pattern matching on even byte boundaries (i.e., 2,4,6,8 offsets). The 2 bytes per unit forces even byte alignment. For
example:
- 0x14 (byte offset)/2 = 0x0A (register ready)
- 0x28 (byte offset)/2 = 0x14 (register ready)
- 0xFC (byte offset)/2 = 0x7E (register ready)
• Length Field—The Length field in the WOL_Pattern_Configuration register specifies the number of clock cycles
required to compare a variable number of bytes, in the RX stream. The Length field uses a unit of measurement
specified in terms of memory arbiter clock cycles. Software should not program this field with a byte value. The Length
field should be programmed with the maximum number of clocks required to compare the largest pattern size for the
nine streams (10/100 mode only).
Table 75: Required Memory Regions for WOL Pattern
Internal Address Range Size Name
0x8000–0x8FFF 8 KB Miscellaneous Memory Region
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