GPIO Pull UP

[lyk]

Hello

     I have a question about MPC5744P, I set PA[0] as GPIO like this:

     Output and input enable， Pull enable  and pull up，

     but in fact PA[0] is in low leavel state, why?

[martin_kovar]

Hello,

this behavior is correct. If you enable output buffer, level of the pin is controller by GPDO register which is 0 by default. And because the pull up resistor is weak, pin stays in low state.  

If you enable input buffer only and enable pull up, pin will be switched to high state.

Hope it helps.

Regards,

Martin

[lyk]

Thank you!