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Ian Rogers

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• Mar 11, 2020

• #1

Just in case someone else falls foul of this..

I have just spent three evenings battling with XC8 v2.05... C99.. I have a pic18f87k22 and couldn't get simulation going let alone for real..
Stupid mistake... XINST was on by default.. WHY!!!! XC8 does not support extended instruction set.. Surely the mad hatters at Microchip could mask that piggin bit out if they don't support it.. I know its there for assembly and asm can be used with XC8, but any C code will not work...

Make my blood boil... I thought it was a C99 thing, but you can change the standard... Didn't help..

Rant over!!

 

P

Pommie

Well-Known Member

Most Helpful Member

• Mar 11, 2020

• #2

The microchip development tool never fail to disappoint me.

Mike.

 

spectrum

Member

• Mar 15, 2020

• #3

Thanks, nice to know, i sometime work on 16f stuff, not still on 18f

Looking the xc8 guide seems 18f code samples do

#pragma config XINST = OFF

Btw, catching this as mandatory seems quite hard. Masking it OFF by c compiler seems a good idea

 

D

Dan Soze

Member

• Mar 20, 2020

• #4

Remember to avoid the all time top blunders:
1) Never get involved with a land war in Asia.
2) Never go up against a Sicilian with death on the line.
3) Never forget to define all the bits in all the configuration words.

 

Ian Rogers

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• Mar 21, 2020

• #5

Dan Soze said:

3) Never forget to define all the bits in all the configuration words.

Click to expand...

Very correct.. However!! My horse bolted ages ago.... Won't happen again..

 

Musicmanager

Well-Known Member

• Mar 21, 2020

• #6

Ian Rogers said:

My horse bolted ages ago....

Click to expand...

Were you defining it's bits ?

S

 

Ian Rogers

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• Mar 21, 2020

• #7

Ahh!! That's probably why... Dang these fetishes..

 

Musicmanager

Well-Known Member

• Mar 21, 2020

• #8

Pommie said:

The microchip development tool never fail to disappoint me.

Click to expand...

I don't think you're alone .. .. .. .. .

.. .. .. .. and in any case, what you do in the privacy of your own workshop is nobody else's business !!


S

 

Ian Rogers

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• Mar 29, 2020

• #9

Whoops.... Another hiccup... This time it was me... But shows compiling isn't always straight forward.
Look at the variable definition...

C:

void interrupt isr(void)
 {
 int x ,t,s,dir1;
 char str[4];
 if(OERR1)
  {
   …………………..

Now later in the function I had this...

C:

  for(x=0;x<5;x++)
   {str[x] = 0; press.Rx[x] = 0;  height.Rx[x] = 0;}

My mistake is the size of str[], should have been 5… But the char array is placed first by the compiler so the overrun over writes x every loop, thus never completing the loop.... I was convinced it was a serial issue as the interrupt was only firing once...

Thing is... This code has been used "as is" extensively without issue, so the newer V2.05 compiles differently to the older versions...

Pitfalls.....

 

P

Pommie

Well-Known Member

Most Helpful Member

• Mar 29, 2020

• #10

We all fall foul of the "count from zero" tripup every now and then.

Mike.