On 6/25/07, Rich wrote: > Thanks for the reply. All information is useful. How much memory did you > add? I have not worked with SPI before so I want to try it with memory and > a 24-bit A/D. > 24-bit A/D, should be a Sigma-Delta one. Take good care of the SPI communication because I am having big problems with the SPI communication to an AD7731 (an 10 year old parts but still a good one for its price). The noise in the SPI clock is causing data to jump to the top or freeze in continuous conversion mode. I am not using a PIC24 though but an ARM7 MCU from TI. Xiaofan -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist