Rapid Prototyping with 16/32 bits MCU

Posted: **Thu Dec 11, 2008 6:32 pm**

Hi you all!
Hello Lubin:

I am trying to understand how the C call function block works but I am stuck. I have just tried to read a variable "data" and put it out . I compare it with a constant and set a port bit if it is greater or iqual. I have attached the C function also. After I compile it I get this error:

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callf4.o(.text+0x0):C:\Documents and Settings\123\Mis documentos\MATLAB\call4_dspic\sources\..\..\callf4.c: Link Error: Cannot access symbol (_data) at an odd address.
C:\Program Files\Microchip\MPLAB C30\bin\bin/pic30-coff-ld.exe: link errors found, deleting executable `..\../call4.coff'
gmake: *** [..\../call4.coff] Error 0xff
### Real-Time Workshop build procedure for model: 'call4' aborted due to an error.
C30 Compiler found
C30 Compiler found
>>

I was trying to attach the .mdl file and the .c function but I do not know how to attach the files.
Can you explain me how to attach files?
Can you tell me what am I doing wrong?

Jose Luis

Posted: **Thu Dec 11, 2008 6:44 pm**

Simon_says wrote:Can you explain me how to attach files?

Hi Jose Luis,

To attach files on this forum, just look below the Save - Preview - Submit buttons, there is a tab : "upload attachement".
It will help to see the model.

Lubin

Posted: **Fri Dec 12, 2008 9:08 pm**

Hi Lubin..
Here are the .mdl and .c files. I am just trying to turn a pair of leds when the ADC reads more than 2.5V or less than 1.5V. I wanted to use the C function call in order to lear how to use it. I decided to use the example format you posted and it compiles succesfully. However, I program the dsPIC30f4012 and it just turns led RD1 on. That´s all it does. No response to ADC input...nothing. Just RD1 on.
Can you suggest me please?

Thanks a lot!

I was trying to see the C call function output with the matlab scope, but there is no output... Is it posible to simulate and check the performance before program the dsPIC?

Jose Luis

Posted: **Sat Dec 13, 2008 2:45 am**

Dear Joze Luis,

Simon_says wrote:Is it posible to simulate [C function block] before program the dsPIC?

No, C function block will have no behaviour in a simulation. (Like all others blocks from the dsPIC library)

I had a quick glande on your model.
Sample time are Ok for every blocks ; thanks ! (It's a common source of error)

I noticed a datatype error in the C file that make the condition (<= 256) always true and the condition ( >= 512) false !

Code: Select all

#include <p30f4012.h>
unsigned char call6(unsigned char Input)
{	
	unsigned char Temp;
	Temp = (Input);

	return Temp;       
}

should be :

Code: Select all

#include <p30f4012.h>
unsigned int call6(unsigned int Inputtt)
{	
	unsigned int Temp;
	Temp = (Inputtt);

	return Temp;       
}

Be aware that a global variable called Input is declared by the simulink model. You also use a variable named Input inside your function (That may cause trouble). You may considere to rename this variable either in your C function file or in the simulink model file or just directly connect ADC to C function Call.

It should works ! However, I did not tested on the dsPIC. Let us know !
Lubin

Posted: **Thu Jan 08, 2009 5:14 pm**

Hi Lubin.. Sorry for the delay of my response...
Happy new year to all of you! This season I did not work at all, but now I have tested the model and I can see what my mistakes were. It works as you suggested!!! I have implemented it in a dsPIC and it is working. Thanks a lot. I am continuing experimenting and learning. I´ll get back to you again soon.

Jose Luis

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