I have made a single layer PCB with on it a Dallas DS80C320, ADconverter , 2 serial ports, I2C and so on.I use XDATA. P0 and P2 are used for XDATA with 27512, 48T08 and 74HCT373. I tested the program with a PICE-51 In Circuit Emulator. When i put the program in the 27512, it did not work, till i put a probe from an oscilloscope on the ALE-pin. I put a capacitor of 33 pF on pin 11 (is connected to the ALE-pin of the procesor) of the 74HCT373 and all is working fine. I think this is not normal. What did i wrong? Kind regards Sjoerd Toonstra