I am trying to determine what code I need to get an 89C51 to output 8 bits connected to a DAC 0806, and which pins to connect between both chips.
My program calculates floating point numbers between 1 and 9 in increments of 0-255.
The Datasheet of the DAC0806 will tell you what signals it requires - it is up to you to choose what pins to use to implement these!
"floating point numbers between 1 and 9 in increments of 0-255"
What???
It will, indeed. I know it is hard that you actually have to read.
Just a word of caution, get the datasheet from the manufacturers website, not from joeblowsdatasheetcollection.com or some such place. Such sites are notorious for carrying datasheets that are outdated in a few cases downright WRONG (e.g. prerelease with errors).
Erik