CCS/MSP430F5528: sqrt Function causes my program to fail when firmware is uploaded in debug mode

Kyle Goble

Part Number: MSP430F5528

Tool/software: Code Composer Studio

I'm using an MSP430 in my device to take light measurements. I take 20 measurements and store them in the array. I wanted to calculate the standard deviation of the measurements, but I am having issues with the sqrt function. I include math.h and sqrt is called in this function:

double standardDeviation (int average, int measurements[], int positions){ //KG 1/8/2017 Calculate the standard deviation of the data set

	double deviation = 0;
	int i = 0;

	for(i = 0; i <= positions; i++){
		measurements[i] = measurements[i] - average;
		measurements[i] = measurements[i] * measurements[i];
		deviation += measurements[i];
	}

	deviation = deviation/positions;
	deviation = sqrt(deviation);

	return deviation;

}

#include <math.h> is at the header of my .c file.

I am using CCS v5.5, compiler TIv4.1.9 with an output format of eabi. The optimization level is set to 0. When I comment out the line that includes sqrt, everything compiles and works as expected. With sqrt included, debug mode is automatically running and when I try to pause it I get an error. When I disconnect the debugger, the inputs and outputs of the device top working.

A few weird things are sqrt text is purple and when I look up the declaration, I have two options; from compiler 4.1.9 and one from 4.2.1

over 7 years ago

0 Keith Barkley over 7 years ago

Guru 42205 points

Can measurements[] hold the square of measurements[]? That might make deviation negative.

Try adding double s = sqrt(2) at the start of main.

0 Kyle Goble over 7 years ago in reply to Keith Barkley

Intellectual 260 points

I should have mentioned this, I replaced the deviation variable inside of sqrt with 4 and commented out the squared measurements line and got the same results

0 Keith Barkley over 7 years ago in reply to Kyle Goble

Guru 42205 points

Sounds like a hosed math lib. This should actually be moved the MSP430 discussion.

0 AartiG over 7 years ago

TI__Guru**** 173310 points

Kyle Goble said:
I am using CCS v5.5, compiler TIv4.1.9 with an output format of eabi.

These are pretty old versions. Could you possibly try with a newer version of CCS and compiler?

0 Kyle Goble over 7 years ago in reply to AartiG

Intellectual 260 points

This is an old project that I was looking to modify slightly. I've had a hard time with newer version of CCS and compilers because with the same unmodified project files and newer tools, the code will not fit onto the MSP430

0 Kyle Goble over 7 years ago in reply to AartiG

Intellectual 260 points

Does the math.h file need to be added manually on the list of files included in the project? I assumed it was part of the compiler but maybe that is my problem. I also don't have it linked on my file search path. Do I need to do something more than putting #include <math.h> at the header of my .c file?

0 AartiG over 7 years ago in reply to Kyle Goble

TI__Guru**** 173310 points

Kyle Goble said:
Do I need to do something more than putting #include <math.h> at the header of my .c file?

For typical CCS projects you shouldn't have to do anything more. By default, the directory where this file resides (the compiler's /include directory) should be added to the project's compiler include paths, so the compiler will search/find the include file in that path. You can double-check the path is set by going to Project Properties->Build->Compiler->include Options.

0 Kyle Goble over 7 years ago in reply to AartiG

Intellectual 260 points

Thank you for the reply. I'm checking the directory and besides the paths I added myself there is also these two paths: "${CCS_BASE_ROOT}/msp430/include" and "${CG_TOOL_ROOT}/include". Neither of those look like compiler include options to me but I'm not sure. Am I missing something?

0 AartiG over 7 years ago in reply to Kyle Goble

TI__Guru**** 173310 points

${CG_TOOL_ROOT}/include points to the /include directory within the compiler tools root directory, which is where math.h is located. So this looks fine.

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CCS/MSP430F5528: sqrt Function causes my program to fail when firmware is uploaded in debug mode