hi,
i have been working on a project to interface a touch screen with a micrcontroller and a character lcd. now when i connect the touch screen as shown in the attached diagram, the voltage from one of the microcontroller pins falls from 4.9 to 4.3 volts. one other thing is that the voltage read from the output pin varies between 0 to 1 approximately whereas when i connect the touch screen without the pull down resistors the voltage varies between 0 and 5V as required. (VDD = 5V)..
so probably the nuisance are the pull down resistrs, the latter still cannot be avoided since if the touch screen is not pressed the output pin would be floating without the pull down resistors.
what can i do? does anybody have some touch screen interface circuit please?
thanks a lot for your help..
regards
i have been working on a project to interface a touch screen with a micrcontroller and a character lcd. now when i connect the touch screen as shown in the attached diagram, the voltage from one of the microcontroller pins falls from 4.9 to 4.3 volts. one other thing is that the voltage read from the output pin varies between 0 to 1 approximately whereas when i connect the touch screen without the pull down resistors the voltage varies between 0 and 5V as required. (VDD = 5V)..
so probably the nuisance are the pull down resistrs, the latter still cannot be avoided since if the touch screen is not pressed the output pin would be floating without the pull down resistors.
what can i do? does anybody have some touch screen interface circuit please?
thanks a lot for your help..
regards