Question: Schemes for using multiple C6x processors ie. using serial ports or HPI for communications between the multiple processors Any Suggestions ?

Answer:

To use multiple C6x's using the Host Port Interface:
The HPI of the slave C6x should be connected to the asynchronous memory interface of the master C6x.

The connections should be as follows:

       ----               ---------
   CE      |-------------|   HCS
           |             |
  BE[1:0]  |-------------|   HBE[1:0]
           |             |
   AOE     |----->o------|   HR/W
           |             |
   ARE     |-------------|   HDS2
           |             |
   AWE     |-------------|   HDS1
           |             |
   EA2     |-------------|   HHWIL
           |             |
   EA3     |-------------|   HCNTRL0
           |             |
   EA4     |-------------|   HCNTRL1
           |             |
   ARDY    |----->o------|   HRDY
       ----               ----------

Using the above scheme, HPIC will be at the base address of the CE space, HPIA will be two words above that, and HPID will be two words above that. Or (assuming CE0):

       HPIC_1  = 0x00400000
       HPIC_2  = 0x00400004
       HPIA_1  = 0x00400008
       HPIA_2  = 0x0040000C
       HPID_1  = 0x00400010  {Do not increment address}
       HPID_2  = 0x00400014
       HPID_1i = 0x00400018  {Increment address]
       HPID_2i = 0x0040001C
 

....Note that the next word address would be HPIC, again. To use multiple C6x"s using a serial port interface:

Simply connect: DX   to DR
                DR   to DX
                FSX  to FSR
                FSR  to FSX
                CLKX to CLKR
                CLKR to CLKX
                CLKS to CLKS  

You would need a DMA channel to service the serial port.