3 Replies Latest reply on Nov 24, 2010 1:14 AM by userc_44805

    Change pin direction on CY8CKIT-001

       Hi all,




      I am a complete noob when it comes to PSoC.


      How can I dynamically set a GPIO pin as input or output, as and when needed (as in the 1-wire protocol) on the PSoC 5?




      In the 1-wire protocol, I have to pull the line low for a certain amount of time, and then "release" the line by setting the pin as an input, and then read the value on the line.




      Can anyone please help me with this?

        • 1. Re: Change pin direction on CY8CKIT-001

          You can change the direction of a port pin by setting the PRTxDM registers. Bidirection mode of a pin is probably your choice.

          • 2. Re: Change pin direction on CY8CKIT-001

            I just made a change in my code to dynamically change a port pin from connecting a digital PSoC block output to CPU data register (PRTxDR). This is simply by setting the bypass bit of the associated pin to zero.




            PRT4GS &= 0xAF;                            // clear P4.4 and P4.6 bypass bit
            PRT4DR |= 0x50;                            // P4.4 and P4.6 = 1

            • 3. Re: Change pin direction on CY8CKIT-001

               Thanks for your replies.




              I tried changing the drive mode, but it did not work. But you guys did point me in the right direction...




              I found the bidirectional mode enable bit. I enabled bidirectional mode and it worked! The PSoC now releases the pin when I enable the bidirectional mode so that I can read the input value. To enable output mode again, I just disable bidirectional mode.




              Even though this works for me, is this the correct way of handling this?