We have a K63F-based custom board. It's equipped with LANxxxx PHY (can't recall the exact type now), which also provides 48MHz to the CPU. The CPU frequency is 96MHz after all. I'm using a quite recent KSDK with FreeRTOS.
I've observed that the MAC can't work at 100Mbps. If I generate ethernet frames on a linux PC directed to the K63F, K63F tends to lose some ethernet frames. If the speed is not more than ~80Mbps, K63F MAC catches all ethernet frames.
In itself this wouldn't be a problem, since 'ethernet pause frames' are intended for devices that can't keep the full 100Mbps pace. The problem is that I haven't seen any trace of pause frames emitted by K63F in Wireshark, however it's set in the KSDL ENET_DRV_Init(...) input structure.
Is there anybody who could successfully use ethernet pause frames? Not neccessarily on K63F, I'm also interested in other Kinetis MCUs.
If the CPU would run at 120Mhz, could it capture all incoming ethernet frames without a loss?