SMSC LAN9312 - Manual (Page 190)

High Performance Two Port 10/100 Managed Ethernet Switch with 32-Bit Non-PCI CPU Interface
Datasheet
Revision 1.4 (08-19-08) 190 SMSC LAN9312
DATASHEET
3 Flow Control on Multicast Frame (FCMULT)
When this bit is set, the Host MAC will assert back pressure when the AFC
level is reached and a multicast frame is received. This field has no function
in full-duplex mode.
0: Flow Control on Multicast Frame Disabled
1: Flow Control on Multicast Frame Enabled
R/W 0b
2 Flow Control on Broadcast Frame (FCBRD)
When this bit is set, the Host MAC will assert back pressure when the AFC
level is reached and a broadcast frame is received. This field has no function
in full-duplex mode.
0: Flow Control on Broadcast Frame Disabled
1: Flow Control on Broadcast Frame Enabled
R/W 0b
1 Flow Control on Address Decode (FCADD)
When this bit is set, the Host MAC will assert back pressure when the AFC
level is reached and a frame addressed to the Host MAC is received. This
field has no function in full-duplex mode.
0: Flow Control on Address Decode Disabled
1: Flow Control on Address Decode Enabled
R/W 0b
0 Flow Control on Any Frame (FCANY)
When this bit is set, the Host MAC will assert back pressure, or transmit a
pause frame when the AFC level is reached and any frame is received.
Setting this bit enables full-duplex flow control when the Host MAC is
operating in full-duplex mode.
When this mode is enabled during half-duplex operation, the Flow Controller
does not decode the Host MAC address and will send a JAM upon receipt
of a valid preamble (i.e., immediately at the beginning of the next frame after
the RX Data FIFO level is reached).
When this mode is enabled during full-duplex operation, the Flow Controller
will immediately instruct the Host MAC to send a pause frame when the RX
Data FIFO level is reached. The MAC will queue the pause frame
transmission for the next available window.
Setting this bit overrides bits [3:1] of this register.
R/W 0b
Table 14.2 Backpressure Duration Bit Mapping
BACKPRESSURE DURATION
[7:4] 100Mbs Mode 10Mbs Mode
0h 5uS 7.2uS
1h 10uS 12.2uS
2h 15uS 17.2uS
3h 25uS 27.2uS
4h 50uS 52.2uS
5h 100uS 102.2uS
6h 150uS 152.2uS
7h 200uS 202.2uS
BITS DESCRIPTION TYPE DEFAULT