Check that all the flags are properly configured for full-duplex mode. I had a similar problem with FCC ethernet where a bit was missing on the config options.
> -----Original Message----- > From: owner-linuxppc-embedded at lists.linuxppc.org > [mailto:owner-linuxppc-embedded at lists.linuxppc.org]On Behalf Of Thomas > Geffert > Sent: Friday, November 01, 2002 4:23 AM > To: linuxppc-embedded at lists.linuxppc.org > Subject: tqm 8260 scc ethernet crc errors > > > > Hello, > > I've problems with receiving packets with an TQM8260 board on the SCC > 10Mbit ethernet interface. > > If I connect two tqm boards directly via an ethernet crossover cable and > send udp packets from one board to another the receiving CPM marks > 1-15% of all packets with an crc error flag (this depends on packet > size and send speed). When I check the udp checksum of the received > packets this check only ails for approx 5-10% of the marked packets, > e.g. > > Send packets in 5s CPM says CRC-Error[1] UDP checksum error > ===================================================================== > 6000 (512 bytes each) 591 / 9.8% 94 / 1.6% > 4850 (512 bytes each ) 220 / 4.5% 34 / 0.7% > > 6000 (128 bytes each) 182 / 3% 43 / 0.7% > > The faster the packets are send and the longer the packets are > the more errors > are detected. If I send the packets with a rate <50 packets/s I got almost > no crc errors. > > I'm very surprised over the errors, as I use a direct connection > between the boards and send only in one direction. In such a case I > would expect to get no errors. Can this be an EMI error of the > physical SCC ethernet interface of the tqm boards? > > I also connected the tqm board via a switch to a PC 10Mbit ethernet > interface and got slightly smaller error rates, but they are still > there. If I use the FCC ethernet interface I don't get this problems. > > Did anyone make similiar experiences or has an idea how this > errors can happen? > > I use the DENX linux-2.4.4-2002-10-06 (patched for RTAI linux 24.1.10) > and enabled full duplex mode in the SCC enet.c driver (without full > duplex I got also crc errors and lots of dropped packets). > > Thomas Geffert > > Footnotes: > [1] I got this value from the scc1 parameter ram field crcec. > > -- > Dipl.-Ing. Thomas Geffert > KEYMILE / Datentechnik Intercom GmbH > Frankenring 14, 30855 Langenhagen, Germany > Tel +49 (0)511 978197-669 / Fax +49 (0)511 978197-670 > mailto:thomas.geffert at keymile.com / http://www.keymile.com > > <<< Since 1st of October 2002 Datentechnik & Ascom Transmission serve > you as KEYMILE >>> > > ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
