SMSC LAN9312 - Manual (Page 280)

High Performance Two Port 10/100 Managed Ethernet Switch with 32-Bit Non-PCI CPU Interface
Datasheet
Revision 1.4 (08-19-08) 280 SMSC LAN9312
DATASHEET
0 Flow Control Busy (FCBSY)
In full-duplex mode, this bit should read logical 0 before writing to the Host
MAC Flow Control (HMAC_FLOW) register. To initiate a PAUSE control
frame, the bit must be set. During a transfer of control frame, this bit
continues to be set, signifying that a frame transmission is in progress. After
the PAUSE control frame’s transmission is complete, the Host MAC resets
the bit to 0.
Backpressure Enable (BkPresEn)
In half-duplex mode, this signal functions as a backpressure enable and is
set high whenever backpressure is transmitted.
Notes:
„ When writing this register, the FCBSY bit must always be zero.
„ Applications must always write a zero to this bit
R/W 0b
BITS DESCRIPTION TYPE DEFAULT