HF MODEM INTERFACE AND SCHEMATIC 
--------------------------------

Note: This is a working document and not perfect - please report
errors, improvements, or your suggestions to the author.

Included in this package is a schematic for a simple interface
for the Motorola DSP56002EVM (evaluation module). The following
files are included:

1) EVMPCB.PCB ... PCB layout in Wintek SmartArtwork format.
2) EVMPCB.CO  ... HPGL format plotfile for component side.
3) EVMPCB.SO  ... HPGL format plotfile for solder side.
4) EVMPCB.SI  ... HPGL format plotfile for silk screen.
5) EVMPCB.SCH ... Orcad3 format schematic
6) EVMPCB.HP  ... HPGL format for schematic.

Putting it together
-------------------
1) The EVM needs NO modifications, however, the optional RS-232 and
   socket for the Flash Eprom MUST be soldered into place. Obtain
   the Flash Eprom (I got mine from JDR for around $8), however,
   leave the socket empty till later. In addition pay attention to the 
   following jumpers:

   a) J12 ... 16K
   b) J13 ... leave open
   c) PC0, PC1 ... closed
   d) RS-232 jumpers all installed. Install the two open 
      positions the same way as the two that is already installed.
   e) J17 ... leave open

2) The PCB plugs into J7, J4, and J2. Note that the height of the headers 
   on the interface PCB must be sufficient to clear the parts on the EVM,
   especially the heatsink.

3) The parts list for the PCB.
   ---------------------------

   a) 8  x 2 header for J7 position   (part No. ??)
   b) 8  x 2 header for J4 position   (part No. ??)
   c) 15 x 2 header for J2 position   (part No. ??)
   d) 2 x 2  posts for extending LED to front panel
   e) 10K ten-turn potentiometer      (Digikey 3299W-103-ND)
   f) 1K  ten-turn potentiometer      (Digikey 3299W-102-ND)
   g) Mini 8-pin DIN socket           (Digikey CP-2280-ND socket)
                                      (Digikey CP-2280-ND plug)
   h) 1/4 or 1/8W carbon film 10% resistors:
      qty 2, 220
      qty 1, 470 
      qty 2, 10K
   i) qty 2, 2N3904 or eq. NPN transistors
   j) ULN2803A integrated circuit - 18 pins (socket optional)
   k) LED - red, LED-green

4) The connections for the 8-pin mini DIN is similar as for the DSP-93:

   1 ... Down
   2 ... PTT
   3 ... not used
   4 ... use for Up on ICOM radios
   5 ... Transmit audio
   6 ... Ground
   7 ... Up (see (4) for ICOM radios)
   8 ... Receive audio


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Johan Forrer
KC7WW, September 1995
e-mail: forrerj@ucs.orst.edu
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