PIC16F873A code help

[jbmartin87]

Hi, guys. I'm an electronic engineering technology student in my final year. It was reccomended to me to use a PIC16F873A (which I now have) for my final project. I need a little help to get started. I've been reading many sites for the past few days and still don't know where to start.

I have some experience with both assembly and c languages. I am currenly working with mikroC and mplab ide. Would prefer to use C.

What I am trying to accomplish: read in 3 digital values from Port C (RC0, RC1, RC2) (port c because of its ST property) and based on some IF statements output a digital value on Port A (RA0).

Also: Can I assign the ports to variables to make working with my IF statements easier?

All help is greatly appreciated! If you need me to clarify anything just ask. Thanks in advance.

 

[jbmartin87]

anybody? or anybody know any good intro tutorials I should look at?

 

[Acetronics]

Hi, JB Martin

IF you really use the Mikro C compiler ... and are supposed to become an engineer.

You MUST have known four things :

1) the HELP tab : most right place in the upper toolbar ...

2) the example folder located here: C:\Program Files\Mikroelektronika\MikroC\Example ... on your HDD

3) The MkE Forums here : mikroElektronika • Index page

4) the MikroE free online books : Books | mikroElektronika


AND Overall ...

THE HOLY MANUAL : https://www.electro-tech-online.com/custompdfs/2010/03/mikroc_manual.pdf

You'll find there much more than all you want to know ...



and remember the '873 is very similar to the '877 ...

Alain

 

[jbmartin87]

thanks for the reply! I'll have a read and see what I can figure out. Thanks.

 

[jbmartin87]

Ok... started to write my code. Bare with me, as I am taking baby steps.

Here's what I have:

void main() {
  PORTB = 0x00; //initialize portb
  PORTC = 0x00; //initialize portc
  TRISB = 0x00; //set portb as output
  TRISC = 0xFF; //set portc as input

  do {
    if(PORTC=0x01) PORTB = 0xFF; //set portb to 0xFF if portc is 0x01
  } while (1); //endless loop
}

When I run it in mikroC software emulator my if statement sets portc to 0x01 which in turn sets portb to 0xff.
What have I done wrong?

Thanks.

 

[Laamane]

If you use only one equal sign, 0x01 is placed to PORTC. Using two equal signs makes it comparison operator.
So I think that should be like this: if (PORTC == 0x01) PORTB = 0xFF;

 

[Macka]

you need == (2 ='s as they are a comparator)

= <- assignment
== <- comparator

Edit: Laamane beat me to it lol

 

[jbmartin87]

ohhh... thanks guys.

I should have known that, but I've been doing alot of work with visual basic lately.

 

[Macka]

ohhh... thanks guys.

I should have known that, but I've been doing a lot of work with visual basic lately.

Visual Basic is a great language (VB6 is anyway), it's a shame C has to have two different operators when VB can get away just fine with one.

 

[jbmartin87]

Need a little help again....

I wrote a simple little program to make all portB output a high value. Tested it in PIC simulator IDE and it works. Next I try programming/burning the chip using USB PIC PRG.

I put the chip in the breadboard and make the following connections: Vdd(Pin 20) = +5V, Vss(Pins 8,19) = Gnd, and Vpp(Pin 1) = +5V. But I am not getting any output on portB. Any ideas on what I am doing wrong?

**broken link removed**

 

[Nigel Goodwin]

What are you using for the clock oscillator?.

 

[upand_at_them]

If you didn't specify a clock source it'll use the internal oscillator. But post your program code so we can see the entire situation.

 

[blueroomelectronics]

The older 16F87x series do not have an internal oscillator.

 

[upand_at_them]

Curse those legacy chips.

 

[jbmartin87]

damn, I thought when I first looked at the data sheet that it said it had an internal oscillator... but turns out I must've been seeing things?!?

Heres a link to the datasheet: https://www.electro-tech-online.com/custompdfs/2010/04/39582b.pdf

Since, timing isn't critical... can I just use RC mode?

Thanks for the help guys, I REALLY apreciate it!!

 

[blueroomelectronics]

RC mode is fine.

 

[xpi0t0s]

Visual Basic is a great language (VB6 is anyway), it's a shame C has to have two different operators when VB can get away just fine with one.

That's because "if (a=b)" is valid and has a different meaning from "if (a==b)". Parsing a string for example: "while (c=str[i++])" will terminate when c==0.

 

[jbmartin87]

k, new question....

If I want to set RB0 high, I can use: PORTB = 0x01

Is there a way to just 'address' that pin? For example RB0 = 1 (I know that doesn't work, but that's the best way I can explain myself)

 

[Electronworks]

Try PORTB |= 0x01

This will keep all port pins unchanged except for bit 0 which will be set to 1 regardless of its previous state

 

[Electronworks]

this is obviously the shortform of

PORTB = PORTB | 0x01