i am trying to interface touchscreen with p89v51rd2 which does not have an adc onboard.
The problem with interfacing an external adc with the muc is that the polling sequence of touchscreen requires you to ground a pin and in the next sequence check the same pin for analog voltage.
If i give touchscreen wire as my adc input, how am i suppose to ground it for polling the other axis..
kindly help if someone has a solution for this 