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uni_student
Joined: 01 Aug 2007
Posts: 38
Location: AUckland, NEW ZEALAND
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| Pointers and a data array - help please |
 Posted: Mon Aug 20, 2007 12:22 am |
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Hi, im following an example for sending voice hex data over spi. Code in example is with different compiler, so I need to know its equivalent to CCS. MP Lab is coming up with errors for accessing each byte and the function line:
| Code: |
unsigned int Sound_Pointer;
Sound_Pointer = 0;
while(Sound_Pointer < sound1_size) {
while(!input(DREQ)){
}
spi_write(sound1[Sound_Pointer]);
Sound_Pointer++;
}
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..........
| Code: |
#define sound1_size 12106
//I AM HAVING PROBLEMS WITH THE FOLLOWING LINE
static unsigned char code sound1[12106] = {
0x52, 0x49, 0x46, 0x46, 0x0E, 0x2E, 0x00, 0x00, 0x57, 0x41, 0x56, 0x45, 0x66, 0x6D, 0x74, 0x20,
0x10, 0x00, 0x00, 0x00, 0x01, 0x00, 0x01, 0x00, 0x11, 0x2B, 0x00, 0x00, 0x22, 0x56, 0x00, 0x00,
0x02, 0x00, 0x10, 0x00, 0x64, 0x61, 0x74, 0x61, 0xBA, 0x2D, 0x00, 0x00, 0x56, 0x01, 0x54, 0x01,
0x58, 0x01, 0x56, 0x01, 0x54, 0x01, 0x5D, 0x01, 0x5D, 0x01, 0x4E, 0x01, 0x50, 0x01, 0x4F, 0x01,
0x49, 0x01, 0x4A, 0x01, 0x46, 0x01, 0x45, 0x01, 0x48, 0x01, 0x53, 0x01, 0x4F, 0x01, 0x51, 0x01,
…………
};
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Ttelmah
Guest
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| Posted: Mon Aug 20, 2007 4:10 am |
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A couple of comments:
1) Remember that in CCS,an integer is 8bit. To access an array of 12000 elements, you need to use an int16.
2) The array is huge. What PIC do you have?. As it stands, the array needs to be copied to RAM (the default behaviour). Has you chip got 12K of RAM?. I can't think of any PIC18 (or even less so, a PIC16), that has this much RAM. If the array is only going to be used without changes, then declare it as 'const', so it'll be stored in ROM. The code looks as though it is written for a chip with more RAM resources than the PIC.
Best Wishes |
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uni_student
Joined: 01 Aug 2007
Posts: 38
Location: AUckland, NEW ZEALAND
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| Posted: Mon Aug 20, 2007 11:59 pm |
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| Quote: | | What PIC do you have?. |
Yeah voice data is huge, that array is only for saying "one". Am using a PIC18F452. Yep i have made it a const now, and after a few other mods finally got it working.
| Quote: | | Remember that in CCS,an integer is 8bit. To access an array of 12000 elements, you need to use an int16. |
It didnt work with "int16" but i managed to find some other example with a similar array size and they used "unsigned long int".
Thanks for your help, definately another big step forward for me, Cheers |
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Ttelmah
Guest
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| Posted: Tue Aug 21, 2007 4:29 am |
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int16, should work, provided you are not using a _very_ old compiler.
These alternatives for the use of 'long' etc., were added a few years ago, and are preferred, since it makes it obvious just what 'length' the integer is. Given that CCS has the default int, as 8bits, and a 'long' as 16, while most compilers use int16 as the default (which is the ANSI definition), while CCS's approach, is the way that K&R originally assumed the sizes would be done, using 'named' sizes, avoids problems with migration latter...
Best Wishes |
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