SCSI DAUGHTERBOARD FOR THE SARDIS TECHNOLOGIES' ST-2900
          =======================================================

(c) 1988 by Sardis Technologies, all rights reserved


MISCELLANEOUS NOTES
-------------------

1) The ST-2900 SCSI host adapter daughterboard is specifically designed for
   the L5380 chip from Logical Devices Inc., and operation with substitute
   parts from NCR, AMD, etc. is not guaranteed.

2) The terminating resistors (RP1, RP2, R2, R3, R4, R5) can probably be
   omitted if the cable between the ST-2900 SCSI host adapter board and the
   SCSI disk controller board is fairly short and terminating resistor packs
   are installed on the SCSI controller.  This reduces power consumption.

3) The schematics show pin 19 of connector P2 connected to IP3 (at connector
   S1 on the FDC board).  However, do not make this connection unless you
   first modify ST-MON 2.04 to have the baud rate code burned into the EPROM
   so that the baud rate jumpers can be removed from IP3 and IP4.


MODIFYING THE ST-2900 FDC BOARD TO ACCEPT THE ST-2900 SCSI DAUGHTERBOARD:
-------------------------------------------------------------------------

1) Install a female header (1 row x 22 pins, solder tail, designed to accept
   .025" square pins) in the FDC board's prototyping area to mate with
   connector P2 of the SCSI board.  Use the third row of holes from the
   inside -- if you look at the solder side of the FDC board, pin 22 of this
   header will occupy the hole immediately above the letter "v" of the
   markings "rev b".  The header is installed from the component side of the
   FDC board and soldered on the solder side.

2) Wire all 22 pins of the single row female header you just installed for P2
   to the appropriate points on the FDC board as per the schematics.
   Remember to use heavier wires for the +5 and ground pins -- note that the
   two innermost rows of holes in the prototyping area on the FDC board are
   bussed (on the solder side), one for +5v, the other for ground.

3) Install a female header (1 or 2 rows x 20 pins, solder tail, designed to
   accept .025" square pins) in the FDC board's prototyping area to mate with
   some of the pins of connector P1 on the SCSI board.  Use the row(s) of
   holes next to the edge of the FDC board.  Note that this female header
   will not have any wires connected to it -- it is there only to provide
   mechanical support to the SCSI board, so may be shorter or longer than
   specified.


ASSEMBLING THE ST-2900 SCSI DAUGHTERBOARD:
------------------------------------------

1) Install IC sockets for U2 and U3.

2) Install the socket for U1 -- use machined contact IC socket terminal
   strips (eg. four AUGAT 510-AG91D-20 strips), as the crossbars of a
   regular IC socket would be in the way of C1, D2, R4, R5, and especially
   P2.

3) Install resistor SIPs RP1 and RP2 -- note the dot on the component layout
   diagram indicating pin 1.

4) Install resistors R1 to R5 -- note that R2 and R3 must be installed
   vertically (ie. stand on end).

5) Install connector P2 (1 row x 22 pin male header with .025" square pins
   on .100" centers, wire wrap pins).  Insert the connector from the
   component side and solder on the solder side.  Be careful not to get any
   solder on that part of the pins that will be inserted into the matching
   female header.  Make sure the connector is at 90 degrees (right angles)
   to the circuit board.  Cut off flush all 22 pins on the component side
   as U1 will be installed over top of P2.

6) Install the 7 jumper wires which are shown as dotted lines on the
   component layout diagram:
    a) use 22 ga. insulated solid wire for the long jumper sandwiched between
       P1 and RP1, as it carries significant current (to pin 1 of RP2)
    b) there is a very short jumper sandwiched between P1 and RP2
    c) one jumper is near pins 1 of U1 and P2
    d) four jumpers are installed underneath U2, on the solder side of the
       board

7) Install capacitors C1 to C3 -- note that C3 must be installed on the
   solder side of the board so it doesn't get in the way of U2 or U3.

8) Install connector P1 (2 row x 25 pin male header with .025" square pins
   on .100" centers, wire wrap pins).  Insert the connector from the
   component side and solder on the solder side.  Make sure the connector is
   at 90 degrees (right angles) to the circuit board.

9) Install the three IC's into their sockets.

10) Plug the SCSI board into the connectors on the FDC board.


SOURCES OF FURTHER INFORMATION
------------------------------

Kilobaud Microcomputing, May '83 pp.26-40:  OS-9 device driver source code
     for a Western Digital (non-SCSI) hard disk controller

BYTE, March '83, April '83, May '83:  SASI adapter for S-100 bus and CP/M

BYTE, May '86, June '86:  SCSI adapter for 64180 SBC and CP/M





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