1 daughter board (where mpc8569e located) is connected to a motherboard via a connector and motherboard connects backplane via anther connector. On system power up, Rapidio reg 158 sometimes shows 01, which means port is un-initialzed. Per eye-diagram shows, the Vdiffpp of Rapidio signal through the connector which connects motherboard to the backplane is about 800mv, seems it will get even worse when adding the backplane attenuation, and the Rapidio signal entering the tsi578 switch may be weaker than the lower bound specified in the spec.
Since there'r two Rapidio transmitter type (long run and short run), we guess to configure the transmitter to long run may improve the signal quality, but unfortunately we haven't find the right register, we use MPC8569 btw.
My question: Is there a regiter that configure the Rapidio transmitter type? Or are there some hardware design related issue that may cause our problem?
