I thought EDN was a magazine targeted at engineers... = "However, this Design Idea presents a solution to the problem. Given the microcontroller=FFs power operating-voltage source, VDD, use the following simple formula to obtain the hex-code value corresponding to an identified input-analog-voltage level: VIN=D7VIN/(VDD/255)=3Dresult value=3Dhex code. = Note that you must round off the result value to a whole number before converting to a hex-code value for better accuracy. The following sample calculation finds the hex-code value for a measured input-analog-voltage level of 1.6V when using a known microcontroller=FFs VDD of 5V:1.6V/(5V/255)=3D81.6=3D82, or $52." Gerhard -- = http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist