lan83c175 Standard Microsystems Corp., lan83c175 Datasheet - Page 14

• Manufacturer Part Number: lan83c175
• Description: Ethernet Cardbus Integrated Controller With Modem Support Corporation
• Manufacturer: Standard Microsystems Corp.

(fragments) are listed. Up to 63 fragments are
allowed.
starting address and length of each buffer.
As in the direct queuing method, the transmit
DMA will copy fragments one at a time into the
local buffer until Transmit Length bytes have
been copied or all of the fragments have been
read. If early transmit is enabled, transmission
will be initiated when enough bytes have been
copied to meet the early transmit threshold.
Otherwise transmission will be initiated when
the entire copy is complete.
The remaining entries specify the
14
When more than one frame is queued, the
transmit DMA will begin copying a second frame
while the first is transmitting.
copying fragments until the entire
loaded or the first transmission has completed.
If
transmission is still in progress, then the
LAN83C175 will stop and wait.
transmission is finished, the LAN83C175 will
post the status into the first descriptor and
immediately initiate the second transmission. If
the transmission completes before the copy is
done, the LAN83C175 will pause between
fragments to post the status and then resume
the copy.
already
transmission
Figure 3 on the following page shows a drawing
of the Transmit Buffer Structure.
the
been
copy
If the early transmit threshold has
will
exceeded
completes
be
initiated
then
while
It will continue
immediately.
the second
When the
the
frame is
first