We use the BCM53128IQLE in unmanaged mode using the reference schematic BCM53128R_Eval_Schem. At power on, the LNK/ACT leds light for approx. 1 second and then turn off and then operate as expected when an Ethernet cable is plugged in (LED comes on when a cable is plugged in and blinks off when activity is detected). On some boards, a LNK/ACT led remains on after power on and then operates in reverse when a cable is plugged in - it goes off when a cable is plugged in and blinks on when activity is detected.
I assume that a power-on selftest operates and is showing something wrong, but I can't find anything in the data sheet that explains this. What is this LNK/ACT led indicating?
The Broadcom Ethernet Switch products did not move to Cypress, only the IoT/Wireless products noted in this document: IoT Solutions Guide
Broadcom is working on setting up a new community for these products under broadcom.com, but until then you will need to contact one of Broadcom's franchised distributors or regional sales people for support.