the Intel's PCI_to_PCI
bridge (21152) between the ADSP-BF535 and the PCI connector. Is there any
use it? Can we connect to the host directly (e.g to the PCI bus connector on
the PC mother board)?
The PCI-to-PCI bridge is used only as voltage translator, because as you know
the BF535 uses 3.3 V signaling for its I/O pins while most computers PCI busses
are 5 V. The bridge does automatic voltage sensing and as such you can connect
the board to either 3.3 V or 5 V systems.