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Conversion Help

 
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Mark W



Joined: 24 May 2009
Posts: 7
Location: Wellington NZ

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Conversion Help
PostPosted: Thu Jun 21, 2012 2:53 pm     Reply with quote
Hi All,

I have a Microchip 18F46K20 starter board and i am am attempting to convert the OLED driver for CCS. I have completed most of the conversion but am stuck on the following:
Code:

void putpixel_vram(unsigned char x,unsigned char y,unsigned char color)
{
   unsigned char *p;
   char m = 0x01 << (y%8);

   p = &vram[y/8][x];

   if(color)
      *p |=  m;
   else
      *p &= ~m;
}


I get a message in the line char m = 0x01 << (y%8);

saying expression must evaluate to a constant. It may be simple but I dont understand what this means.

Any help would be welcome.

Cheers

Mark
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Thu Jun 21, 2012 3:33 pm     Reply with quote
Put the declaration of 'm' and the assignment on separate lines:
Quote:

unsigned char *p;
char m;

m = 0x01 << (y%8);
Mark W



Joined: 24 May 2009
Posts: 7
Location: Wellington NZ

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PostPosted: Thu Jun 21, 2012 3:49 pm     Reply with quote
Thanks PCM,

This now compiles until I get to
Code:
p = &vram[y/8][x];

Which says too many subscripts.
Are these things just different syntax between compilers ?
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Thu Jun 21, 2012 3:53 pm     Reply with quote
1. Post a link to the source code that you are trying to convert.

2. Also post your CCS compiler version. Example of version numbers:
http://www.ccsinfo.com/devices.php?page=versioninfo
Mark W



Joined: 24 May 2009
Posts: 7
Location: Wellington NZ

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Link to Microchip PIC18FXK20 Starter Kit
PostPosted: Thu Jun 21, 2012 7:49 pm     Reply with quote
http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1406&dDocName=en535806

I am converting the OLED drive in the demo software

I have version 4.71 of the compiler
PCM programmer



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Posts: 21708

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PostPosted: Thu Jun 21, 2012 7:54 pm     Reply with quote
Quote:
I have version 4.71 of the compiler

There is no such version. Did you look at the link I provided ?
Mark W



Joined: 24 May 2009
Posts: 7
Location: Wellington NZ

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PostPosted: Thu Jun 21, 2012 8:10 pm     Reply with quote
My apologies 4.071
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Fri Jun 22, 2012 12:28 am     Reply with quote
Quote:

This now compiles until I get to
p = &vram[y/8][x];
Which says too many subscripts.

I think you can do a work-around by substituting this line for it:
Code:

p = vram[y/8] + x;

This code gets the base address of the desired vram_x array, and
then adds 'x' to it. The pointer arithmetic should work OK.
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