LAN9218I_12 Datasheet, PDF (29/134 Pages) SMSC Corporation – High-Performance Single-Chip 10/100 Ethernet Controller with HP Auto-MDIX and Industrial Temperature Support

High-Performance Single-Chip 10/100 Ethernet Controller with HP Auto-MDIX and Industrial Temperature Support
Datasheet
Destination Address Source Address ……………FF FF FF FF FF FF
00 11 22 33 44 55 00 11 22 33 44 55 00 11 22 33 44 55 00 11 22 33 44 55
00 11 22 33 44 55 00 11 22 33 44 55 00 11 22 33 44 55 00 11 22 33 44 55
00 11 22 33 44 55 00 11 22 33 44 55 00 11 22 33 44 55 00 11 22 33 44 55
00 11 22 33 44 55 00 11 22 33 44 55 00 11 22 33 44 55 00 11 22 33 44 55
…CRC
It should be noted that Magic Packet detection can be performed when LAN9218i is in the D0 or D1
power states. In the D0 state, “Magic Packet” detection is enabled when the MPEN bit is set. In the
D1 state, Magic Packet detection, as well as wake-up frame detection, are automatically enabled when
the device enters the D1 state.
3.6
Host Bus Operations
3.6.1 32-bit vs. 16-bit Host Bus Width Operation
The LAN9218i can be configured to communicate with the host bus via either a 32-bit or a 16-bit bus.
An external strap is used to select between the two modes. 32-bit mode is the native environment for
the LAN9218i. Ethernet controller and no special requirements exist for communication in this mode.
However, when this part is used in the 16-bit mode, two writes or reads must be performed back to
back to properly communicate.
The bus width is set by strapping the EEDIO pin; this setting can be read from bit 2 of the “Hardware
Configuration Register”. Please refer to Section 5.3.9, "HW_CFG—Hardware Configuration Register,"
on page 77 for additional information on this register.
3.6.2 16-bit Bus Writes
The host processor is required to perform two contiguous 16-bit writes to complete a single DWORD
transfer. This DWORD must begin and end on a DWORD address boundary (A[2] and higher, cannot
change during a sixteen bit write). No ordering requirements exist. The processor can access either
the low or high word first, as long as the next write is performed to the other word. If a write to the
same word is performed, the LAN9218i disregards the transfer.
3.6.3 16-bit Bus Reads
The host processor is required to perform two consecutive 16-bit reads to complete a single DWORD
transfer. This DWORD must begin and end on a DWORD address boundary (A[2] and higher, cannot
change during a sixteen bit read). No ordering requirements exist. The processor can access either
the low or high word first, as long as the next read is performed from the other word. If a read to the
same word is performed, the data read is invalid and should be re-read. This is not a fatal error. The
LAN9218i will reset its read counters and restart a new cycle on the next read. The Upper 16 data
pins (D[31:16]) are not driven by the LAN9218i in 16-bit mode. These pins have internal pull-down’s
and the signals are left in a high-impedance state.
3.6.4 Big and Little Endian Support
The LAN9218i supports “Big-” or “Little-Endian” processors with either 16 or 32-bit busses. To support
big-endian processors, the hardware designer must explicitly invert the layout of the byte lanes.
3.6.5 Word Swap Function
Internally the LAN9218i is 32-bits wide. The LAN9218i supports a Word Swap Function when its Host
Bus Interface is configured to operate in 16-bit mode. This feature is controlled by the Word Swap
SMSC LAN9218i
29
DATASHEET
Revision 2.9 (03-01-12)