VME Address Map of Hydra-II
                    ------------------------------



                                                        Rev.   7-JUN-1994 

We are using A24 VME addressing with Hydra II VME base addresses of:
$00A0 0000  for Hydra II number A,   $00B0 0000  for Hydra II number B,
and  $00C0 0000  for Hydra II number C.  

Because rational VME accesses to the Hydra II are D32 accesses the highest
address in a block shown below is the highest Long Word address (i.e. 3
less than the highest byte address that is part of the block.

The following diagram shows the layout of Hydra II number A.


                      +---------------------------------+
         $A1 FFFC     |                                 |
         $A1 1000     |      Reserved  Do not use.      |
                      +---------------------------------+

                      +---------------------------------+
         $A1 0FFC     |   JTAG Test Bus Controller      |
         $A1 0C00     |   No details are shown yet.     |
                      +---------------------------------+


                      +---------------------------------+
         $A1 0BFC     |     Alias of the Hydra-II       |
         $A1 0820     |     Main Control Registers      |
                      +------------------------+--------+
         $A1 081C     | DSP #4 Interrupt Cntrl | Access |
         $A1 0818     | DSP #3 Interrupt Cntrl | as Long|
         $A1 0814     | DSP #2 Interrupt Cntrl | Words. |
         $A1 0810     | DSP #1 Interrupt Cntrl | Only   |
                      +------------------------+ data   |
         $A1 080C     | DSP #4 Boot Control    | bits   |
         $A1 0808     | DSP #3 Boot Control    | D7:D0  |
         $A1 0804     | DSP #2 Boot Control    | are    |
         $A1 0800     | DSP #1 Boot Control    | signif.|
                      +------------------------+--------+

                      +---------------------------------+
         $A1 07FC     |     Interrupt Controller        |
         $A1 0400     |     No Details Shown Yet.       |
                      +---------------------------------+

                      +---------------------------------+
         $A1 03FC     |     Alias of the Semaphores     |
         $A1 0020     |      Reserved  Do not use.      |
                      +-----------------+---------------+
         $A1 001C     |   Semaphore 7   |               |
         $A1 0018     |   Semaphore 6   |   Access as   |
         $A1 0014     |   Semaphore 5   |   VME Long    |
         $A1 0010     |   Semaphore 4   |   Words.      |
         $A1 000C     |   Semaphore 3   |   Only data   |
         $A1 0008     |   Semaphore 2   |   bit  D0 is  |
         $A1 0004     |   Semaphore 1   |   significant.|
         $A1 0000     |   Semaphore 0   |               |
                      +-----------------+---------------+

                      +---------------------------------+
         $A0 FFFC     |  Reserved for Expansion of the  |
                      |     Shared Dual Port Memory     |
         $A0 8000     +---------------------------------+

                      +------------------+--------------+
         $A0 7FFC     | DSP #1 Hydra Mon*|              |      8000 1FFFh
                      |   Control Area   |              |
         $A0 7FC0     |     16 words     |    Shared    |      8000 1FF0h
                      +------------------+     Dual     |
         $A0 7FBC     | DSP #2 Hydra Mon*|     Port     |      8000 1FEFh
                      |   Control Area   |    Memory    |
         $A0 7F80     |     16 words     |   32 KBytes  |      8000 1FE0h
                      +------------------+              |
         $A0 7F7C     | DSP #3 Hydra Mon*|              |      8000 1FDFh
                      |   Control Area   |              |
         $A0 7F40     |     16 words     |              |      8000 1FD0h
                      +------------------+              |
         $A0 7F3C     | DSP #4 Hydra Mon*|    Shared    |      8000 1FCFh
                      |   Control Area   |     Dual     |
         $A0 7F00     |     16 words     |     Port     |      8000 1FC0h
                      +------------------+    Memory    |
         $A0 7EFC     | DSP #1 Hydra Mon*|   32 KBytes  |      8000 1FBFh
                      |  Data Xfer Area  |              |
         $A0 7B00     |    256 words     |              |      8000 1EC0h
                      +------------------+              |
         $A0 7AFC     | DSP #2 Hydra Mon*|              |      8000 1EBFh
                      |  Data Xfer Area  |              |
         $A0 7700     |    256 words     |    Shared    |      8000 1DC0h
                      +------------------+     Dual     |
         $A0 76FC     | DSP #3 Hydra Mon*|     Port     |      8000 1DBFh
                      |  Data Xfer Area  |    Memory    |
         $A0 7300     |    256 words     |   32 KBytes  |      8000 1CC0h
                      +------------------+              |
         $A0 72FC     | DSP #4 Hydra Mon*|              |      8000 1CBFh
                      |  Data Xfer Area  |              |
         $A0 6F00     |    256 words     |              |      8000 1BC0h
                      +------------------+              |
         $A0 6EFC     |    User Area*    |              |      8000 1BBFh
                      |  in the Shared   |              |
                      | Dual Port Memory |    Shared    |
                      |  $5F00  KBytes   |     Dual     |
         $A0 1000     |   17C0h KWords   |     Port     |      8000 0400h
                      +------------------+    Memory    |
         $A0 0FFC     |  HydraMon*       |   32 KBytes  |      8000 03FFh
                      |  Boot Area       |              |
                      |  for DSP 1:4     |              |
                      |  1 KWords        |              |
         $A0 0000     +------------------+--------------+      8000 0000h

       VME Address                                             C40 Address


    NOTE:   HydraMon is NOT USED in the L1.5 Cal Trig.  Therefore, all of
            the Shared Dual Port Memory is available as "user space."


Notes:
------


Recall that in VME; the address of a Long Word (i.e. a 32 bit data type) is
the lowest VME byte  address of a byte that is  part of the Long Word. In
VME this lowest address byte is the the MSByte of the Long Word.

Recall the details of how addressing works in VME and in a VAX:

VME Longword Format is addressed by the address of the MSByte
-------------------    and the MSByte comes first in memory.

 -------  -------  -------  -------      -------  -------  -------  -------
 | MSB |  |     |  |     |  | LSB |      | MSB |  |     |  |     |  | LSB |
 |3   2|  |2   1|  |1    |  |     |      |3   2|  |2   1|  |1    |  |     |
 |1   4|  |3   6|  |5   8|  |7   0|      |1   4|  |3   6|  |5   8|  |7   0|
 -------  -------  -------  -------      -------  -------  -------  -------
    N                                      N+4


VAX Longword Format is addressed by the address of the LSByte
-------------------    and the LSByte comes first in memory.

 -------  -------  -------  -------      -------  -------  -------  -------
 | LSB |  |     |  |     |  | MSB |      | LSB |  |     |  |     |  | MSB |
 |     |  |1    |  |2   1|  |3   2|      |     |  |1    |  |2   1|  |3   2|
 |7   0|  |5   8|  |3   6|  |1   4|      |7   0|  |5   8|  |3   6|  |1   4|
 -------  -------  -------  -------      -------  -------  -------  -------
    N                                      N+4



To the extent that a C40 has external data types other than 32 bit; is it
a big endian or little endian machine?  Note that, in the Shared Dual Port
Memory, the data is in the VME Longword Format (i.e. big endian).