![background image](http://html.mh-extra.com/html/national-semiconductor/st-nic-dp83902a/st-nic-dp83902a_manual_710381019.webp)
7.0 Packet Reception
(Continued)
6. Place the ST-NIC in either mode 1 or mode 2 loopback.
This can be accomplished by setting bits D2 and D1, of
the Transmit Configuration Register, to ‘‘0,1’’ or ‘‘1,0’’,
respectively.
7. Issue the START command to the ST-NIC. This can be
accomplished by writing 22H to the Command Register.
This is necessary to activate the ST-NIC’s Remote DMA
channel.
8. Remove one or more packets from the receive buffer
ring.
9. Reset the overwrite warning (OVW, overflow) bit in the
Interrupt Status Register.
10. Take the ST-NIC out of loopback. This is done by writ-
ing the Transmit Configration Register with the value it
contains during normal operation. (Bits D2 and D1
should both be programmed to 0.)
11. If the ‘‘Resend’’ variable is set to a 1, reset the ‘‘Re-
send’’ variable and reissue the transmit command. This
is done by writing a value of 26H to the Command Reg-
ister. If the ‘‘Resend’’ variable is 0, nothing needs to be
done.
Note 1:
If Remote DMA is not being used, the ST-NIC does not need to be
started before packets can be removed from the receive buffer ring. Hence,
step 8 could be done before step 7.
Note 2:
When the ST-NIC is in STOP mode, the Missed Talley Counter is
disabled
Received Packet Aborted If It Hits Boundary
TL/F/11157 – 13
18
Obsolete