2 transmit poll demand register (tx_poll_demand), Transmit poll demand register (tx_poll_demand) – SMSC LAN9420 User Manual
Page 105
Single-Chip Ethernet Controller with HP Auto-MDIX Support and PCI Interface
Datasheet
SMSC LAN9420/LAN9420i
105
Revision 1.22 (09-25-08)
DATASHEET
4.3.2
Transmit Poll Demand Register (TX_POLL_DEMAND)
This register enables the TX DMA engine to check for new descriptors.
Offset:
0004h
Size:
32 bits
BITS
DESCRIPTION
TYPE
DEFAULT
31:0
Transmit Poll Demand (TPD)
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.
WO
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