High Performance Two Port 10/100 Managed Ethernet Switch with 32-Bit Non-PCI CPU Interface

Datasheet

BITS

 

DESCRIPTION

TYPE

 

DEFAULT

 

 

 

 

 

 

 

3

Flow Control on Multicast Frame (FCMULT)

R/W

 

0b

 

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

 

 

 

 

 

 

 

 

 

 

2

Flow Control on Broadcast Frame (FCBRD)

R/W

 

0b

 

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

 

 

 

 

 

 

 

 

 

 

1

Flow Control on Address Decode (FCADD)

R/W

 

0b

 

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

 

 

 

 

 

 

 

 

 

 

0

Flow Control on Any Frame (FCANY)

R/W

 

0b

 

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.

 

 

 

 

 

 

 

 

 

 

 

 

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

 

 

 

 

 

 

 

 

Revision 1.4 (08-19-08)

190

SMSC LAN9312

 

DATASHEET