I am using PowerPC 440 EP. The PHY I am using is DP83848. I have enabled RMII mode. I am making sure that all the registers are configured for this mode only, by reading back the registers.
First i tried enabling internal loopback in PowerPC by enabling the ILE bit in EMAC0_MR1 register. There was no issue. Then I wanted to test external loopback without RJ-45 cable. that is the data transmitted by Power PC is loop backed by the PHY. So i disabled the ILE bit and enabled FullDuplex FDE bit in EMAC0_MR1 register (As illustrated in the PowerPC User Manual). I also enabled Internal Loopback in PHY.I had no issues in this also. I was able to receive the looped back packets from the PHY. Also to make sure that PHY has no issue, there is a built in test facility avaiilable in the PHY. I also enabled that bit and cleared for the passing of the Built In Test of the PHY. But i never tried doing loop back with the RJ-45 cable. But when i cleared the loop back along the PHY path, should i also test looping back with the cable?? Thanks for your response. Thanks & Regards, Prathika R Stefan Roese wrote: > On Friday 10 April 2009, prathika wrote: >> i am porting uboot in PowerPC 440. >> i tried using the ping command.i have connected my board to PC via cross >> cable. >> When i monitor on the PC side using Network Monitor, >> the PC receives the ARP request packet and the PC is replying with >> acknowledgement. >> I verified reading the receive status register in PPC, it shows there >> was FCS error and the EMAC rejects the received packet. > > Which 440 variant are you using? And which PHY (in which connection mode, > MII, > RGMII...)? > >> Actually i enabled external loop back in PowerPC and made appropriate >> configuration in PPC and in the PHY chip.I have no issues in receiving >> the packet.things work absolutely fine. > > Are you doing an internal loopback test (using the loopback test mode of the > EMAC, or such a test mode of the PHY) or are you using an real external > loopback test, using an external RJ45 loopback connector? > > You might want to take a look at the 4xx POST ethernet driver and tests. It's > possible to use internal and external loopback tests here (see > CONFIG_SYS_POST_ETHER_EXT_LOOPBACK). > >> but when it comes to peer to >> peer communication, i have problem.. should i doubt on my hardware?? > > Sure. If it's not working then it's always possible that such problems result > from hardware issues. > >> what >> can be the possibilities?? has anyone faced such an issue? > > I suggest you check your PHY and it's components. Sometimes a wrong resistor > or capacitor can cause such or similar problems. > > Best regards, > Stefan > > ===================================================================== > DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel > HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany > Phone: +49-8142-66989-0 Fax: +49-8142-66989-80 Email: off...@denx.de > ===================================================================== _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot