Why the 502 remote power-on operation does not work in the compact PC

[OneStop Systems]

Product: OSS-502  (OSS-PCIe-HIB68-x16) and OSS-370 card (OSS-PCIe-HIB38-x16)

Question:

Why the OSS-502 remote power-on operation does not work in the compact PC but the OSS-370 works?

I have a XYX Compact PC and it is connected to an OSS CUBE3 unit. See attached diagram.

The CUBE3 has a HIB68-X16 TARGET card and it is linked to  compact PC via 4 miniSAS PCie cables.

Inside the PC there is an OSS HIB68-X16 HOST card in which the 4 miniSAS PCIe cables are connected.

Answer:

The 502 remote-on operation is only specified to be used in server-type computers.

The specific reason is that when server system power plug is inserted, it creates AUX power before the unit is turned on.

The FPGA that is on the 502 needs this AUX power to properly operate the CMI sequencing.  Most regular PCs do not have AUX power powered separately.

It is generally turned on at the same time as the main 3.3V so the FPGA is not initialized properly and CMI does not work. 

Do not attempt to use 502 cards in non-server applications requiring remote power on.
The 370 board does not use a FPGA and power on signals are sent with discrete signals, whereas the 502 must use IIC.