                       "DataPump" the 6551 ACIA Card
                   (C)opyright Perry M. Grodzinski, 1991

           "DataPump Plus" contra "SwiftLink, DataBlast, CommPort"
                       upgrade by Frank Kontros 1996

Note: You are free to give away these documents but not to sell!

SwiftLink, DataBlast & CommPort  are respective Trademars of their copyright
owners!

In original "DATAPUMP" card there is a problem to finding out  AA4890  DC-DC
converter chip.  Now, there are many RS232 driver/receiver chips with built-
in DC-DC converter  (e.g. MAX 230, 232, 235, 237).  This  chips  needs  less
external componets than AA4890. I decided to use the cheap MAX 232. It costs
now ca. 1.5-2 US$. There are also many other chips AD232, ICL232, etc.  with
MAX232  full  compatibility.  This  chip contains 2 RS232 drivers/receivers.
Don't use MAX232A because it needs other external capacitor values.

Two additional jumpers installed:  J1 for $DE00/$DF00 (IO1/IO2) ACIA address
selection,  and  J2  for  IRQ/NMI selection (for use ACIA with fast ACIA IRQ
handlers, e.g. OS/A65).

R2-R4 resistors pulls up default levels when no modem connected  (no  hangup
while program initializes modem).

If  you  want  to  use  it  also with C128, then 6551A or 8551 chips must be
installed.

Instead of simple 3.6864Mhz quartz oscillator,  on-crystal  generator may be
used.  In this case you must connect OUT  to  XTAL1 (6),  XTAL2 (7) pin must
float and power must be connected to crystal as follows:

                         _________________________
                         |                        \
                         |  N.C.              GND  |
                         |  O                  O   |
                         |                         |
                         |                         |
                         |  O                  O   |
                         |  +5V               OUT  |
                          \_______________________/


                R6551 PINOUT                        MAX232 PINOUT

             +---------------+                        +-------+
       GND --| 1          28 |-- R-/W          +cap1 -|1 \/ 16|- Vcc
       CS0 --| 2          27 |-- o2            +cap3 -|2    15|- GND
      /CS1 --| 3          26 |-- /IRQ          -cap1 -|3    14|- T1out
      /RES --| 4          25 |-- DB7           +cap2 -|4    13|- R1in
       RxC --| 5          24 |-- DB6           -cap2 -|5    12|- R1out
     XTAL1 --| 6          23 |-- DB5           -cap4 -|6    11|- T1in
     XTAL2 --| 7          22 |-- DB4           T2out -|7    10|- T2in
      /RTS --| 8          21 |-- DB3            R2in -|8     9|- R2out
      /CTS --| 9          20 |-- DB2                  +-------+
       TxD --| 10         19 |-- DB1
      /DTR --| 11         18 |-- DB0
       RxD --| 12         17 |-- /DSR
       RS0 --| 13         16 |-- /DCD
       RS1 --| 14         15 |-- Vcc
             +---------------+

"DataPump Plus" now  fully  compatible with SwiftLink, DataBlast & CommPort.
Furthermore, many new jumper(able) options added.

I must admit, that I never seen any SwiftLink, DataBlast or CommPort.

Good Luck!

Frank Kontros  (jeno@kontr.uzhgorod.ua)