Christian

Certainly an interesting approach. The way I had intended was just the opposite, to set up 80 blocks of 5 bytes. This would be so that when a 'keypress' was read from code you would just have to inc dptr to get the next byte, which is better??? There is one problem, which may very well be no problem at all. After an output (thru a 74hc138 decoder) on the 8255, one of the lines on the 8031 data bus is driven low, after a cpl I have 1 logic high data line, it is NOT a bin/hex code. What I orginally attempted was to send this through a bunch of CJNE statements to get a BCD code for the line that was pressed for the upper nibble (column). After this I would use the lower nibble to hold the 8255 output data (row). This would allow me to assign 1 byte per key but, it was just a mess of code. Is there an easier approach to all of this??? I am certainly open to all suggestions.

Ben