LAN9118_07 Datasheet, PDF (80/129 Pages) SMSC Corporation – High Performance Single-Chip 10/100 Non-PCI Ethernet Controller

High Performance Single-Chip 10/100 Non-PCI Ethernet Controller
Table 5.3 Valid TX/RX FIFO Allocations (continued)
Datasheet
TX_FIF_SZ
TX DATA FIFO
SIZE (BYTES)
TX STATUS FIFO
SIZE (BYTES)
RX DATA FIFO
SIZE (BYTES)
RX STATUS FIFO
SIZE (BYTES)
4
3584
512
11520
768
5
4608
512
10560
704
6
5632
512
9600
640
7
6656
512
8640
576
8
7680
512
7680
512
9
8704
512
6720
448
10
9728
512
5760
384
11
10752
512
4800
320
12
11776
512
3840
256
13
12800
512
2880
192
14
13824
512
1920
128
In addition to the host-accessible FIFOs, the MAC Interface Layer (MIL) contains an additional 2K
bytes of TX, and 128 bytes of RX FIFO buffering. These sizes are fixed, and cannot be adjusted by
the host.
As space in the TX MIL (Mac Interface Layer) FIFO frees, data is moved into it from the TX data FIFO.
Depending on the size of the frames to be transmitted, the MIL can hold up to two Ethernet frames.
This is in addition to any TX data that may be queued in the TX data FIFO.
Conversely, as data is received by the LAN9118, it is moved from the MAC to the RX MIL FIFO, and
then into the RX data FIFO. When the RX data FIFO fills up, data will continue to collect in the RX
MIL FIFO. If the RX MIL FIFO fills up and overruns, subsequent RX frames will be lost until room is
made in the RX data FIFO. For each frame of data that is lost, the RX Dropped Frames Counter
(RX_DROP) is incremented.
RX and TX MIL FIFO levels are not visible to the host processor. RX and TX MIL FIFOs operate
independent of the TX adatand RX data and status FIFOs. FIFO levels set for the RX and TX data
and Status FIFOs do not take into consideration the MIL FIFOs.
Revision 1.3 (05-31-07)
80
DATASHEET
SMSC LAN9118