Posted Thu Mar 1, 2012 2:48 PM
Sorry, i was thinking better and it's both too small to be an accelerator card, nor it seems to suppose to fit a 6800 CPU.
Check if the STe has a 1.44Mb floppy, i think they needed to work in 16mhz to read high density discs. The female could have had a 'stick' to change between 8mhz and 16mhz.
28 pins could be right for the floppy controller.
It would to know to wich chip it was plugged.