topic Re: exp,log and other math functions using CW for MCU Development Studio v10.6 and an MC9S08PA8 in 8-bit Microcontrollers

exp,log and other math functions using CW for MCU Development Studio v10.6 and an MC9S08PA8

efthymioskondos — Wed, 03 Feb 2016 15:01:38 GMT

Dear community,

I am transfering a part of code from one MCU vendor (Atmel xmega32E5) to Freescale/NXP MC9S08PA8 MCU ,

and when I use the log function from math.h (i hope like other IDEs does) the MCU "hits" endless restarts.

If i comment this line, MCU does its supposed job without any issue and i can see an ADC result on debugger crystal clear.

unsigned int temp;

double ftemp;

void main(void)

{

System_Init(); //Initialise system hardware/software modules

for(;;)

{

temp=ADC_Get_Sample(CH11); //Read current channel ADC value (54us@8MHz)

ftemp=log(((10240000/temp) - 10000)); //Endless restart occurs - CRITICAL point

}

1) How /When do i update/include the "math.h" or similar (?) library header ?

2) Does this IDE support floats and doubles for "small ones" like the PA16 MCU?

(I have chosen at the beggining bareboard project with IIEE 64bit float support)

Best Regards,

Tim

Re: exp,log and other math functions using CW for MCU Development Studio v10.6 and an MC9S08PA8

Stano — Fri, 05 Feb 2016 13:19:37 GMT

Hello Efthymios,

it is possible to use the math functions in CW10.6. You need just include it:

#include <math.h>

It adds the math.h file from the installed CW package.

I hope this helps you.

Best Regards,

Stano.

Re: exp,log and other math functions using CW for MCU Development Studio v10.6 and an MC9S08PA8

kef2 — Fri, 05 Feb 2016 14:10:49 GMT

Default stack size set in PRM file is too short for S08 math functions.

Re: exp,log and other math functions using CW for MCU Development Studio v10.6 and an MC9S08PA8

efthymioskondos — Mon, 08 Feb 2016 08:37:21 GMT

Thank you Edward & Stanislav for your fast response ,

I will look into it as for math.h and modify(increase) the stack size of S08.

See how it goes, and get you feedback as soon as possible.

Cheers,

Tim

Re: exp,log and other math functions using CW for MCU Development Studio v10.6 and an MC9S08PA8

efthymioskondos — Mon, 08 Feb 2016 09:57:19 GMT

FIY ,

SOLVED according to Edward Karpicz and Stanislav suggestion.

So to use logx,log , exp functions , include your <math.h> on your project and also go to

Project Settings->Linker_Files->Project.prm , open file with double click

and edit STACKSIZE from 0x80 (128bytes default size), to a bigger numer.
But beware, not to kill the entire RAM area by entering exotic hex number (For me it worked for 256bytes (0x100).

Cheers,