function never execute but code compile - c

Question

I'm trying to run the following code in c on a beaglebone black (microcontroller running Debian).
The code compiles but terminates right when the pwm_init() function is called.
No printf will execute after this line, even the first in the pwm_init() function.
I tried removing pwm_init(), and then wait_for_pwm() will run normally.
This is a code to setup an interrupt timer on the beaglebone in order to communicate with a DAC through SPI.
The code was running and could communicate before this adding.
/*
*Filename: mems.c
*SPI test program to communicate with AD5666 DAC on Micro Mirror Driver board */
#include <stdint.h>
#include <stdio.h>
#include <fcntl.h>
#include <stdlib.h>
#include "iolib.h"
#include <unistd.h>
#define DELAY_NS 62500 // Timer period in ns
// PRU Interrupt control registers
#define PRU_INTC 0x00020000 // Start of PRU INTC registers TRM 4.3.1.2
#define PRU_INTC_GER ((volatile uint32_t *)(PRU_INTC + 0x10)) // Global Interrupt Enable, TRM 4.5.3.3
#define PRU_INTC_SICR ((volatile uint32_t *)(PRU_INTC + 0x24)) // Interrupt, TRM 4.5.3.6
#define PRU_INTC_GPIR ((volatile uint32_t *)(PRU_INTC + 0x80)) // Interrupt, TRM 4.5.3.11
// PRU ECAP control registers (i.e. PWM used as a timer)
#define ECAP 0x00030000 // ECAP0 offset, TRM 4.3.1.2
// Using APWM mode (TRM 15.3.2.1) to get timer (TRM 15.3.3.5.1)
#define ECAP_TSCTR ((volatile uint32_t *)(ECAP + 0x00)) // 32-bit counter register, TRM 15.3.4.1.1
#define ECAP_APRD ((volatile uint32_t *)(ECAP + 0x10)) // Period shadow, TRM 15.3.4.1.5, aka CAP3
#define ECAP_ECCTL2 ((volatile uint32_t *)(ECAP + 0x2a)) // Control 2, TRM 15.3.4.1.8
#define ECAP_ECEINT ((volatile uint16_t *)(ECAP + 0x2c)) // Enable interrupt, TRM 15.3.4.1.9
#define ECAP_ECCLR ((volatile uint16_t *)(ECAP + 0x30)) // Clear flags, TRM 15.3.4.1.11
// R30 is the GPIO register
// R31 is the interrupt register
#define NUMBER_OF_COEFS 87
int xn[NUMBER_OF_COEFS] = { 0 };
int ynn[NUMBER_OF_COEFS] = { 0 };
int xy[2];
static double coefs[NUMBER_OF_COEFS] = { -0.003874396983162784,-0.0037425007502381417,0.0007168162935488041,-0.0015837981969284466,0.001324731958160302,0.000940030114550933,0.002909179571989647,0.002970492669088027,0.0037475240063036684,0.003135242276391628,0.002431551570668268,0.0007465565198417194,-0.0010918847362976609,-0.0032610680167253635,-0.0050886443383995035,-0.0064219306251743396,-0.0067757336585719885,-0.00603689840577871,-0.004073405037328031,-0.001084864753089533,0.002607744624181485,0.006446336960328277,0.009805149887731802,0.012005211009068262,0.01248315933178856,0.010855477027307714,0.007038206816858291,0.0013011753812607633,-0.005726736257811221,-0.013085733616184817,-0.019608024169477135,-0.024024160014903175,-0.025137566107801428,-0.022018671074884637,-0.01412798218138592,-0.0014477915111131118,0.015482420337480308,0.03556527369143834,0.057256428960766804,0.07871540989639365,0.09799912606296178,0.1132905004893123,0.12311069228747347,0.1265004803246064,0.12311069228747347,0.1132905004893123,0.09799912606296178,0.07871540989639365,0.057256428960766804,0.03556527369143834,0.015482420337480308,-0.0014477915111131118,-0.01412798218138592,-0.022018671074884637,-0.025137566107801428,-0.024024160014903175,-0.019608024169477135,-0.013085733616184817,-0.005726736257811221,0.0013011753812607633,0.007038206816858291,0.010855477027307714,0.01248315933178856,0.012005211009068262,0.009805149887731802,0.006446336960328277,0.002607744624181485,-0.001084864753089533,-0.004073405037328031,-0.00603689840577871,-0.0067757336585719885,-0.0064219306251743396,-0.0050886443383995035,-0.0032610680167253635,-0.0010918847362976609,0.0007465565198417194,0.002431551570668268,0.003135242276391628,0.0037475240063036684,0.002970492669088027,0.002909179571989647,0.000940030114550933,0.001324731958160302,-0.0015837981969284466,0.0007168162935488041,-0.0037425007502381417,-0.003874396983162784};
#define REF_ON 0x01000008 //command to turn on internal VREF
#define X_OFFSET 3
#define Y_OFFSET 0
#define X_DRIVE 1
#define Y_DRIVE 2
#define SIZEMAT 2
float tabx[SIZEMAT] = { -100, 100 };
float taby[SIZEMAT] = { -100, 100 };
// Forward definitions
int convert_spi(int dac_val,int channel); //formats bytes for write function
inline void pwm_init();
inline void wait_for_pwm_timer();
int* fir_filterXY(int x, int y);
int main(int argc, char **argv){
int i, fd, debug=0, loop=0, user_loop=0;
int x_off=-1, y_off=-1;
int x_val=-1, y_val=-1;
int freq = -1;
unsigned int buf = REF_ON;
unsigned int dac_value = 1; // 0 to 65535 value to set dac output
unsigned int spi_bytes = 0; // spi communication bytes to send
char direction = 0; // Direction of triangle wave ramp
fd = open("/dev/spidev1.0", O_RDWR);
if(fd < 0) printf("spi failed to open\n");
iolib_init();
//Set LDAC control pin to output
iolib_setdir(9,15,1);
//Tying LDAC low will update dac channel as soon as it has new data
pin_low(9,15); //sel0
write(fd,&buf,4); //set internal vref on
// User loop
int valx = 0;
int valy = 0;
int* ass;
int assx = 0;
int assy = 0;
int i = 0;
int freqcnt = 0;
int freqi = 0;
if (freq>1000)
{
freq = 1000;
}
if (freq<1)
{
freq = 1;
}
freqcnt = (int)((1000000000/DELAY_NS)/freq - 1);
spi_bytes = convert_spi(32000, X_OFFSET);//format bytes for write function
write(fd, &spi_bytes, 4);
spi_bytes = convert_spi(32000, Y_OFFSET);//format bytes for write function
write(fd, &spi_bytes, 4);
printf("In user loop with movement frequency of:%i\n", freq);
pwm_init();
valx = 32000;
valy = 32000;
assx = 32000;
assy = 32000;
printf("starting\n");
while (1){
wait_for_pwm_timer();
spi_bytes = convert_spi(assx, X_DRIVE);//format bytes for write function
write(fd, &spi_bytes, 4);
spi_bytes = convert_spi(assy, Y_DRIVE);//format bytes for write function
write(fd, &spi_bytes, 4);
freqi++;
if(freqi >= freqcnt){
valx = (int)((tabx[i]+100) * 320);
valy = (int)((taby[i]+100) * 320);
freqi = 0;
i++;
if (i >= SIZEMAT)
i = 0;
}
ass = fir_filterXY(valx, valy);
assx = *(ass);
assy = *(ass+1);
}
return 0;
}
/* Function: convert_spi
*
* Takes a dac value (0-65535) and a dac channel (or all channels) and generates the appropriate 32bits to send to AD5666 via SPI
*
* INPUTS
* dac_val: sets the voltage output with voltage output= 2.5*(dac_val/65535)
* channel: selects which dac channel to update with dac_val. 0=DACA ,1=DACB, 2=DACC, 3=DACD, 16=all
*
* RETURNS
* spi_data: integer value to send via spi using to update channel with new dac value
*/
int convert_spi(int dac_val,int channel){
int spi_data=0;
unsigned int nibble1;
unsigned int nibble2;
unsigned int nibble3;
unsigned int nibble4;
nibble1= dac_val & 0xF000;
nibble2= dac_val & 0x0F00;
nibble3= dac_val & 0x00F0;
nibble4= dac_val & 0x000F;
spi_data |=(nibble1>>4);
spi_data |=(nibble2<<12);
spi_data |=(nibble3<<12);
spi_data |=(nibble4<<28);
spi_data |=(channel<<12);
return spi_data;
}
// Initializes the PWM timer, used to control output transitions.
// Every DELAY_NS nanoseconds, interrupt 15 will fire
inline void pwm_init(){
printf("Intereupt setup");
*PRU_INTC_GER = 1; // Enable global interrupts
printf("1");
*ECAP_APRD = DELAY_NS / 5 - 1; // Set the period in cycles of 5 ns
printf("2");
*ECAP_ECCTL2 = (1<<9) /* APWM */ | (1<<4) /* counting */;
printf("3");
*ECAP_TSCTR = 0; // Clear counter
printf("4");
*ECAP_ECEINT = 0x80; // Enable compare equal interrupt
printf("5");
*ECAP_ECCLR = 0xff; // Clear interrupt flags
printf("done\n");
}
// Wait for the PWM timer to fire.
// see TRM 15.2.4.26x
inline void wait_for_pwm_timer() {
register unsigned int __R31;
while (!(__R31 & (1 << 30))) {} // Wait for timer compare interrupt
*PRU_INTC_SICR = 15; // Clear interrupt
*ECAP_ECCLR = 0xff; // Clear interrupt flags
}
int* fir_filterXY(int x, int y){
int i = 0;
double temp = 0;
for (i = 0; i < NUMBER_OF_COEFS - 1; i++)
{
xn[i] = xn[i + 1]; //xn est au bout
}
xn[NUMBER_OF_COEFS-1] = x;
//multiplier par les coef
for (i = 0; i < NUMBER_OF_COEFS; i++)
{
temp += xn[NUMBER_OF_COEFS - i] * coefs[i];
}
xy[0] = (int)(temp+0.5);
for (i = 0; i < NUMBER_OF_COEFS - 1; i++)
{
ynn[i] = ynn[i + 1];
}
ynn[NUMBER_OF_COEFS-1] = y;
temp = 0;
for (i = 0; i < NUMBER_OF_COEFS; i++)
{
temp += ynn[NUMBER_OF_COEFS - i] * coefs[i];
}
xy[1] = (int)(temp + 0.5);
return xy;
}

Answer 1

A couple of recommendations:
printf() can occasionally lag in its output. To be very sure that nothing is being printed, call fflush(stdout) after the print line. This will flush the stdout buffer-- if nothing is printed after the flush, then the println() really is not being executed.
How is your program terminating? If execution does not continue past the pwm_init() function, that almost certainly means that something bad is happening with the memory locations you are writing to. Double check that your register values are correct and that your program isn't being killed due to invalid memory access.