Input pin PTA4 not reading HIGH even when forced HIGH externally

[TKB]

I am using the FXTH870912DT1 and by default the PTA4 pin is supposed to work as an input. In my code, Background mode is disabled, and I read the PTA4 pin and it does not read HIGH even though I have forced it HIGH through an external MCU's GPIO. 

The PTA4 pin has been also externally pulled HIGH to VDD using a 4.7 kOhm resistor. I have also measured the voltage at PTA4 pin using a multimeter and it is reading 3.25V.

So what am I doing wrong here?

Thanks

Tushar

[JozefKozon]

Dear Tushar,

could you please state from which register are you trying to read it in the PTA4? Is it from the PTADD register?

With Best Regards,

Jozef 

[TKB]

Hi Jozef

I am trying to read from the PTAD register, Bit 4.

Regards,

Tushar

[JozefKozon]

Dear Tushar,

there shouldn't be a problem to read the Bit 4 high in the PTAD register if there is 3.25V on the PTA4 pin. Could you please double check how is the Bit 1 BKGDPE set in the SIMOPT1 register?

Could you please check the VDD voltage? The high voltage on the PTA4 pin should be minimally 0.7*VDD.

With Best Regards,

Jozef 

[TKB]

Hi Jozef

Just to be doubly sure, I explicitly made the BKGDPE bit to 0.

SIMOPT1 = (SIMOPT1 | SIMOPT1_STOPE_MASK | SIMOPT1_COPE_MASK ) & (UINT8)(~((UINT8) (SIMOPT1_COPCLKS))) & (UINT8)(~((UINT8)(SIMOPT1_BKGDPE_MASK)));

Still, it doesn't work.

Regards,

Tushar

[JozefKozon · Accepted solution]

Hi Tushar,

I have contacted an application engineer for an advice. For his answer please see the description.

I apologize for confusion and inconvenience. 

DESCRIPTION

PTA4 pin has two functions: BKGD and GPIO output-only. PTA4 cannot be used as GPIO input. I see that the FXTH8709xx datasheet indicates that the pin is input-only, and this is an error. It has been corrected it the datasheets/manuals of the other part numbers, but not this one apparently. Sorry for the confusion.

With Best Regards,

Jozef

[TKB]

Thanks for the clarification Jozef.

Tushar