>Then, each time you boot, you can take your four fixed >constants and multiply them by this SF to get the >"calibrated" values you store in RAM to compare with >the raw ADC values. Why do it each time it boots? Why not do it in the cycle he reads the accurate reference, and then store the scaled values? -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist