ride

Ports PTB3, PTB4 and PTB5 on MC9S08GW, Open drain function only?

Discussion created by ride on Aug 29, 2011
Latest reply on Aug 30, 2011 by bigmac

How do you get the GPIO ports PTB4 and PTB5 to work as full complimentary outputs?  The datasheet does not indicate that these pins are open-drain only, but I can only get these to operate as open drain outputs.  I had to add external pull-ups to PTB4 and PTB5 to get desired output functionality.  The internal pull-ups were too weak for my application.

 

Just setting the PTBDD register only provides open-drain operation.  I tried clocking the IIC module and enabling the module, with the same result.  If I put the IIC module into the Master mode, I lose control of the I/O.

 

Thanks for the input on this problem.

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