Hi Peet,

on using the 2051, parallel output was not a good choice.
Since it occupy to many i/o lines (2051: only 15 available).

If no fast speed needed, serial output was always better.
E.g. the Philips PCF8591 need only 2 wires to the micro.
Also I2C software can easy be implement.
E.g. look at:
http://www.specs.de/~danni/appl/hard/i2c/index.htm


Peter