Single-Chip Ethernet Controller with HP Auto-MDIX Support and PCI Interface

Datasheet

4.3.2Transmit Poll Demand Register (TX_POLL_DEMAND)

 

Offset:

0004h

Size:

32 bits

 

 

This register enables the TX DMA engine to check for new descriptors.

 

 

 

 

 

 

 

 

BITS

 

DESCRIPTION

 

 

TYPE

DEFAULT

 

 

 

 

 

 

31:0

Transmit Poll Demand (TPD)

 

 

WO

-

 

When written with any value, the DMAC will check for frames to be

 

 

 

transmitted. If no descriptor is available, the transmit process returns to the

 

 

 

suspended state and bit 2 of the DMAC_STATUS register (transmit buffer

 

 

 

unavailable - TU) is not asserted. A write to this register is only effective if

 

 

 

the transmit process is in the suspended state. A Read of this register will

 

 

 

timeout and invalid data will be returned.

 

 

 

 

 

 

 

 

 

 

 

SMSC LAN9420/LAN9420i

105

Revision 1.22 (09-25-08)

 

DATASHEET