mc9s08pa16 poblems with porta2 and porta3

[slanfys]

Hello I've come to you as my last resort because I am not able to configure a simple pins.

I want porta as a output. I set port_ptad = 0x0F and port_ptaoe = 0x0F

in other hand I realice that porta2 and porta3 can operate as a sci or iic, so I set SYS_SOPT1 register, bit IICPS = 1. And so, i set my pins as I/O port.

When I try to test all pins it turns out that porta2 and porta3 don't have tensions. 

At the end, I came to datasheet to study SDA(PTA2)/SCL(PTA3) structure (page 148 datahseet) and I cannot understand how I could send tension to the output pins.

Thanks!

[slanfys]

Yes I know, but how could I come out data from there?

[vicentegomez]

Hi

recommend that you add an external pull up ( if you do not have it yet) and use the following code (this is just for the PTA2 )

//PTA2's Output Enable Register is set to enable output
PORT_PTAOE_PTAOE2 = 1 ;
//PTA2 pin is driven low 
PORT_PTAD_PTAD2 = 0;

....

PORT_PTAD_PTAD2 = 1;

Also you can set the internal pull up but I recommend using the external one

PORT_PTAPE_PTAPE2  = 1; // internal pull up enable

I hope this will help you

Regards

[vicentegomez]

Hi

Please be aware that the 

 PTA2 and PTA3 operate as true-open drain when working as output

I hope this will help you

have a good day