Hi to all,
I am facing a problem with my newly designed board specially on PHY IC(DP83848C) and few GPIO's. I am using LPC2388.
I received a new version of hardware which has all hardware's placed are same as previous board at least for Ethernet circuit. In my previous version of board all parts are working well.
With my new board i tried to write and read the Phy registers. I succeed on reading and writing to the Phy registers. But its always saying Link is broken and not available.
My speed LED is always high. When i connect RJ45 with my board no Link lED nor Ack LED is blinking. I would like to know what are the Ways available to debug my board specially on Ethernet circuit?
I would like to know what are the Debugging methods are mandatory and available to check a Phy IC whether its communicating with my Controller as well as to the network. I checked all the possible hardware connections. All are connected well.
If you face this kind of problem what you will do to diagnose the problem?
Please ask me if you are not clear at any point.
There is one thing I would try to do if I wanted to find out why the PHY is reporting that there is no link.
1. Get a device with an ethernet port configured for 10 Mbit/s. This could be a PC with ethernet adapter configured appropriately. Why 10 Mbit/s? Because 10 Mbit/s signals are easy to see with a scope. 2. Connect the aforementioned device with your board. 3. With a scope, inspect the signals received by your board.
If all goes well, you should see the so-called 'normal link pulses.' Check polarity and levels of the pulses, make sure they are correct. If your PHY is receiving normal link pulses, it should report that a link is established.
Thanks for your reply.
When i read the Link register when actually a link was presented, the return value of PHY said that there is no link. In the Init_ethernet(), before checking the Link status my LPC_EMAC.c code puts the PHY to Autonegotiation mode. But if read the PHY its not able to complete the Autonegotiation complete.
So i believe problem starts here. The document says the status of three LEDs at Reset/power-Up indicates the status of the ANAR reg. So is my PHY IC is not coming out of reset mode?
Link status bit in BMSR is defined by IEEE 802.3u Clause 22. It indicates if the link was lost since the last time this register was read. Its name (given by IEEE) is perhaps misleading. A more accurate name would have been the “Link lost” bit. If the actual present link status is desired, then either this register should be read twice or depending on the PHY, read the PHYSTS (0x10 bit 0 for 83848) register.