Abstract: An A/D conversion method which compares an input analog voltage and a comparison voltage, wherein the comparison voltage range corresponds to the upper half or lower half of the previous comparison voltage range if the determination of the previous bit was normal, and when the previous comparison was abnormal, then the comparison voltage range is outside of the previous comparison voltage range.

Abstract: An automatic wiring device for deriving the shortest distance wiring route in a short time, in designing a semiconductor integrated circuit. First, based on the coordinate positions of respective signal terminals and the coordinate positions of respective channel wiring areas of respective lines, the X-coordinate positions of all of the partial wiring routes ay1, ay2 . . . , by1, by2 . . . , ayr2, byr2, ayr3, byr3 extending in the Y-direction are determined. Then, based on the positional relations among respective partial wiring routes extending in the Y-direction in respective interlinear wiring areas, the Y-coordinate positions of all of the partial wiring routes ax1-2-3, bx1-2-3, axr2-4-r3, bxr2-r3, axr3-5-6, bxr3-3-4 extending in the X-direction are determined. By these determinations, the wiring routes WA, WB for connecting the signal terminals of respective groups, in a network form, with the shortest distance, are determined.