topic hRe: pull up question in 8-bit Microcontrollers

pull up question

yecosuma — Sun, 11 Apr 2010 22:20:02 GMT

I want use a pull up in PTC OF THIS MCU MC9S08LC60 BUT i obtain this message

error at location 1838 attemp to write to read-only location

the port register PTCPE IS READ AND WRITE I DONT HAVE BECAUSE HAPPEN THIS THANKS NEWLY FOR YOU ANSWER

Re: pull up question

peg — Mon, 12 Apr 2010 06:02:19 GMT

Hello yecosuma,

Perhaps you could show us how you are trying to do this.

hRe: pull up question

yecosuma — Mon, 12 Apr 2010 10:31:22 GMT

the configuration is normal

PTCDD_PTCDD0 =0;
PTCD_PTCD0=0;
PTCPE_PTCPE0 =1;

have i that set other register?

Re: hRe: pull up question

Darkn3ss — Sun, 18 Apr 2010 03:10:55 GMT

This is quite interesting. I don't think this is the case, but the compiler may actually be warning you that you are writing the value of PTCD pin 0, which you set as an input the line above (inputs are read-only).

I also prefer to set the pullups prior to setting the direction, but that is just me.

PTCDD_PTCDD0 =0;
PTCD_PTCD0=0; //Deleting this line won't do any harm.
PTCPE_PTCPE0 =1;

Re: hRe: pull up question

yecosuma — Sun, 18 Apr 2010 07:37:08 GMT

thanks for you aclaration but it not working; i dont know the cause; this pins have others funtion; in code warrior debug not present error or warning but in true time simulator occur Error: At location 1838 -
Error: Attempt to write to a read-only location just when simulating the instrution PTCPE_PTCPE0=1;. what pass this in all pins of this port?