我正在尝试在beaglebone black（运行Debian的微控制器）上运行以下代码。
代码编译但在调用pwm_init()函数时终止。
此行之后不会执行printf，即使是pwm_init()函数中的第一行也是如此。
我尝试删除pwm_init()，然后wait_for_pwm()将正常运行。
这是在beaglebone上设置中断计时器的代码，以便与DAC通过SPI进行通信。
代码正在运行，可以在添加之前进行通信。
/*
*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;
}
答案 0 :(得分：0)
一些建议：
printf()偶尔可能会滞后于其输出。要确保没有打印任何内容，请在打印行后调用fflush(stdout)。这将刷新stdout缓冲区 - 如果在刷新后没有打印任何内容，则println()确实没有被执行。
您的计划如何终止？如果执行没有继续超过pwm_init()函数，那几乎可以肯定意味着您正在写入的内存位置发生了一些不好的事情。仔细检查您的寄存器值是否正确，以及您的程序是否因内存访问无效而被终止。