On 9/23/06, Xiaofan Chen wrote: > I could have used SPI directly. However I am facing a practial > limitation that SPI simply requires too many optocouplers. A SPI would require three optocouplers if I don't mistake, two for data and one for clk. It's quite interesting you want separate ADC than a multiplexed solution. That means you need isolation for every channel ? You're designing a sort of recording device ? Vasile -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist