Problem in A Port of Pic and Programming

[Pravin Gosavi]

Hello. I am doing my mini project. I have Pic16f628a. It have two ports A & B.
What I am doing take input from A and give output at B. I have pulled up the A.
Ok. Upto this I had no problem. But while programing I had tested my pic in so many ways. Sometimes it gives flicker (Leds) on output pins. Doesn't take input from A.
So I tried just simple blinking of leds. It also sometimes blinks, sometimes not, When I bring my finger near to microcontroller Blinking stops. I have programed from different pickit2. On pcb circuit, on breadboard with three different Chips. Since I have three Pic16f628A. Also reinstalled Mplab and Hi tech c compilers. Checked power supply (with multimeter). Where I am doing mistake. PLZ HELP. :-(

 

[Joe G]

https://www.electro-tech-online.com/threads/pic-newcomers-please-read-upd-0xd1.15035/

 

[Ian Rogers]

We need two things...... Circuit and code..... Most pic16f628a problems are to do with the comparators one of your first commands needs to load the CMCON register with 7, then port A will be digital....

 

[JimB]

Most pic16f628a problems are to do with the comparators one of your first commands needs to load the CMCON register with 7, then port A will be digital....

I got caught with that little trap myself just a couple of days ago!.
A hour or so of head scratching, why does this crazy port not work?
RTFM - the CMCON register - instant fix.

JimB
(Overdosing on smilies)

 

[Pravin Gosavi]

Thnks. I want to know why and how to do this..

 

[Ian Rogers]

Thnks. I want to know why and how to do this..

What!

Do you have code and a circuit???? If you check the links in my signature... Nigel's tutorials are in ASM and I have recoded them into C.. All you need is there..

 

[Pravin Gosavi]

Ok thnk u so much. I will check.

 

[JonSea]

You should fine some useful information here: Commandments For Using PICs.

It's a compilation of many common "gotchas."

 

[Pravin Gosavi]

Thank u so much experts. Solved my problem.
If any one having same problem or is beginner read-
cmcon=0x07

TRISA=0xff not "TRISA=1"

If (-----==1) "not" if (----=1)

Also have good connections of ICSP while programming. Don't use breadboard while u program a chip.

 

[Ian Rogers]

Ahh! Simple gotya! At least you'll never make THAT mistake again...