Problem with handling open drain output of PIC 16f84a

[gonewiththewind]

Hi!
I'd like to output RA4 as 0 and 1 alternatively 0.5sec each time,not constant.But I am not successful.I can't handle open drain output.
Loop: Poke PortA,16
Pause 500
Pause PortA,0
Pause 500
Goto Loop
In my program, what's wrong?or something else?Pls......

 

[asahin11]

Re: pic 16f84a

Hi gonewiththewind,

You should try to connect a pull up resistor between RA4 and +5V, its value 10K.

regrads,

 

[xmli1976]

pic 16f84a

RA4 is open drain so if you want to output ra4 of value 1,you have to pull up it to vdd through a resistor with value of 10k typically