Other Parts Discussed in Thread: DP83869,
I have a board with a DP83869 setup in gigabit FMC mode, it works great when the device connected to the copper Ethernet supports gigbit, but it does not work when device does not support gigabit.
I have LED0 set low, LED1 and LED2 set low. According to the datasheet this should allow autonegotiation on the copper Ethernet of both 100M and gigabit. This does in fact happen, both speed devices bring up a propper link, BUT the optical connection to the other box does not work when a 100Mb device is connected. Looking at the signal going to the SFP cage the signals look identical in both cases but SOMETHING is different because the other box does not connect when 100Mb device is plugged int o the FMC box.
I tried setting the fiber force mode but that didn't make any difference. The datasheet says that when LED0 is 0 fiber autonegotiation is enabled and 1 is fiber force mode. But elsewhere it says the fiber speed is not dependent on autonegotiation. This is a bit confusing.
SO is there anyway to make it work, that when a 100Mbit device is plugged into the copper Ethernet jack that the optical will properly connect to the other box that is just gigabit optical?
John S.