ON/OFF CONTROL FOR BI-DIRECTIONAL(READ AND WRITE) LINE ON MY CPU

Thread Starter

MSahin

Joined Feb 22, 2018
8
Hello, I want to design a TFT Evolution board for my two types of TFT and Touch Panel. But to control the bidirectional (Read & Write) line on my cpu, I need a circuit that will allow me to turn it on/off. Do you have any suggestions for this?
 

Papabravo

Joined Feb 24, 2006
18,125
Hello, I want to design a TFT Evolution board for my two types of TFT and Touch Panel. But to control the bidirectional (Read & Write) line on my cpu, I need a circuit that will allow me to turn it on/off. Do you have any suggestions for this?
What CPU?
What Read & Write line?
Why do you think it is bidirectional?
 

Thread Starter

MSahin

Joined Feb 22, 2018
8
I am sorry about that. I am using dsPIC33EP256MU810 on my motherboard. I want to use a pin for interrupt to control the capacitive touch screen interrupt pin. But sometimes I use this pin as an output, and sometimes I want to separate the pin of my processor from this structure and make it idle. So I need a control circuit to control my bidirectional path (This line will be used for two types of pins-> input and output)
 

Papabravo

Joined Feb 24, 2006
18,125
I am sorry about that. I am using dsPIC33EP256MU810 on my motherboard. I want to use a pin for interrupt to control the capacitive touch screen interrupt pin. But sometimes I use this pin as an output, and sometimes I want to separate the pin of my processor from this structure and make it idle. So I need a control circuit to control my bidirectional path (This line will be used for two types of pins-> input and output)
I'm having trouble visualizing what you are talking about. Words are nearly useless when it comes to describing circuits.
A general solution for having one processor pin that can handle 2 inputs and 2 outputs would be four tristate buffers. Something like this:

1640273461212.png

ONLY one of the enable signals should be low at one time and you would also have to configure the uP_Pin properly. If you truly want bidirectional I/O you can enable one input buffer and 1 output buffer.
 
Top