enabling weak pull up

[JUZAR]

in PIC12F615, kindly advise how to enable single port pin GP3 as weak pull up.

[medelec35]

You will need to use a C code block.
The C code will have to be in lower or upper case depending on your version of Flowcode.
What is your version of Flowcode?

[Benj]

Hello,

In the device datasheet there is this in the notes regarding the weak pullups.

1: Global GPPU must be enabled for individual pull-ups to be enabled.
3:The GP3 pull-up is enabled when configured as MCLR in the Configuration Word, otherwise it is disabled as an input and reads as ‘0’.

Not sure if this means GP3 weak pullup is only on when the global GPPU bit is set or on anyway but the C code to set the GPPU bit would look like this.

Flowcode 6 and previous

Code: Select all

option_reg = option_reg | 0x80;

Flowcode 7 and after

Code: Select all

OPTION_REGbits.GPPU = 1;

[medelec35]

Hi Ben,
As it's

Code: Select all

NOT GPPU

I thought GPPU has to be cleared for WPU to be enabled?

OPTION_REGbits.GPPU = 1;

causes an errror:

Code: Select all

12F615 Weak pull ups .c: main()
    77:	OPTION_REGbits.GPPU = 1;
	                    ^ (255) not a member of the struct/union ""
	                       ^ (182) illegal conversion between types
int -> volatile union S50
(908) exit status = 1

As it's NOT GPPU it should be:

Code: Select all

OPTION_REGbits.nGPPU = 1;

I don't believe GP3 has a weak pull-up that works?
All the other pins do.

[Benj]

Aha yes I missed the line, negating the operation

Thanks for checking