Do you have a pull up resistor on the data pin ?

Pailoor

dvdmods wrote:

  Hello  allI have problem with i2c serial communicationI have written some code to send data to serial device I am using pin 6 on 12c508 as clock,and pin 5 as data The code only works if I have my oscilloscope on pin 5 (data)if I take it of the pin the code wont work anymore.the device I am communicating with uses standard i2c protocol I have used the same code to talk to other devices on the same bus with no problemsbut on this device I have this problem any one no why?? I think I can solve the problem with resistor or capacitor on pin 6 to earthBut dont want to use anymore components any help will be greatly appreciated