6 Port Paddleboard Card
                        for Hydra II DSP Board
                              Revision A
                _______________________________________

                                                            18-MAR-1994 

          Michigan State University-High Energy Physics, D0 Trigger
                                                

Description
-----------

    The Six Port Paddleboard (SPPB) is a card which connects to the
25-pin D-micro-mini connectors on the Hydra-II card.  It brings the
signals on these miniature connectors out to "normal" 24-pin 0.1" x 0.1"
connectors.  The large connectors will be used to receive twist-n-flat
cables from the CRC card, or to either send or receive twist-n-flat
cables to/from other DSP Comm Ports.

    The twist-n-flat cables will use signal/ground pairs in order to 
preserve maximum signal fidelity.

    To understand the mapping of 25-pin D-micro-mini connectors, refer
to the file:

        TRGHARD:[10_COMM]6_PORT_PADDLE_KEYIN_NETLIST.TXT.  

IMPORTANT NOTE
--------------

    The Hydra-II schematics sent to us by Ariel are incorrect.  Ariel 
placed incorrect pin numbers on the D-micro-mini connectors.  The
Hydra-I and Hydra-II User's Guides are CORRECT.

    The Keyin Netlist for the SPPB was made using the (incorrect)
schematic.  Therefore the Keyin Netlist for the SPPB is wrong.  

    The SPPB is usable if the 24-pin 0.1" x 0.1" pin spacing connectors
are placed on the SOLDER SIDE of the SPPB.  This is what we have done
to allow the SPPB to be usable.

    Both the correct and incorrect pinouts of the 25-pin D-micro-mini
connectors can be found in the file:

        MSUTRGROOT:[D0_TEXT.LEVEL_15.CALTRIG.HARDWARE_SOFTWARE_TEXT]
            CABLES_CRC_TO_DSP_AND_DSP_TO_DSP.TXT