Cheap 38400 Bps ACIA Card
(DataPump Plus)

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.

• J1 for $DE00/$DF00 (IO1/IO2) ACIA address selection;
• J2 for IRQ/NMI selection (for use ACIA with fast ACIA IRQ handlers, e.g. OS/A65).

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

Note: If you want use it with C128, you'll need install either 6551A or 8551 chip.

Instead of simple 3.6864Mhz quartz oscillator, on-crystal generator could be used. In that case you must connect OUT to XTLI (6), XTLO (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

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

Good Luck!