2008-06-17 09:50:12     problems with ppi

2008-06-17 09:50:12     problems with ppi

tom R (FRANCE)

Message: 57409   

  Hello!

I am testing a small program to test the ppi, but I can't visualize anything on PPI's pins with a probe. The kernel configuration seems to be good. I can only see a signal on port Tx. I have read a lot of docs. (ppi, timers) but I think I need someone gives me a hand. Here is my code:

#include <stdio.h>

#include <fcntl.h>

#include <sys/ioctl.h>

#include <unistd.h>

#include <errno.h>

#include <string.h>

#include <stdlib.h>

#include <sys/time.h>

#include "ppi.h"

#define Taille 8

// static ssize_t ppi_write(struct file *filp, const char *buf, size_t count, loff_t *f_pos)

int main () {

    int fd, retval;

    unsigned char data_write[Taille]={1,2,3,4,5,6,7,8};

     //unsigned char data_write[Taille]={0,0,0,0,0,0,0,0};

    // unsigned char data_read[Taille];

    close("/dev/ppi0");

    //fd = release("/dev/ppi0", O_RDWR);

    fd = open ("/dev/ppi0", O_RDWR);

    if (fd < 0) {

        printf("Error opening dev/ppi \n");

    }

    printf("Début de la configuration ioctl \n");

    ioctl(fd, CMD_PPI_PORT_ENABLE,CFG_PPI_PORT_ENABLE);  

    ioctl(fd, CMD_PPI_XFR_TYPE, CFG_PPI_XFR_TYPE_NO_SYNC);

    ioctl(fd, CMD_PPI_PORT_CFG, CFG_PPI_PORT_CFG_NA);  

    ioctl(fd, CMD_PPI_FIELD_SELECT, CFG_PPI_FIELD_SELECT_1);   

    ioctl(fd, CMD_PPI_PACKING, CFG_PPI_PACK_DISABLE);

    ioctl(fd, CMD_PPI_SKIPPING, CFG_PPI_SKIP_DISABLE);

    ioctl(fd, CMD_PPI_SKIP_ODDEVEN, CFG_PPI_SKIP_ODD);

    ioctl(fd, CMD_PPI_DATALEN, CFG_PPI_DATALEN_8);        

    ioctl(fd, CMD_PPI_CLK_EDGE, CFG_PPI_CLK_EDGE_RISE);

    ioctl(fd, CMD_PPI_TRIG_EDGE, CFG_PPI_TRIG_EDGE_RISE);

    ioctl(fd, CMD_PPI_LINELEN, CFG_PPI_DATALEN_8);      

    ioctl(fd, CMD_PPI_SET_DIMS, CFG_PPI_DIMS_1D);

    ioctl(fd, CMD_PPI_DELAY, PPI_READ_NODELAY);      

    ioctl(fd, CMD_PPI_PORT_DIRECTION, CFG_PPI_PORT_DIR_TX);

    ioctl(fd, CMD_PPI_SETGPIO);               

    ioctl (fd, CMD_PPI_GET_ALLCONFIG);

    printf("\n Fin de la configuration ioctl \n");

      

    int compteur=0;

    printf("\n Ecriture des données \n");

    do {

      

        retval=write(fd, data_write, Taille);

        if ( retval != Taille ) {

            perror("ppi write error\n");

            return 0;

        }

        printf("OK \n");

        compteur++;

        sleep (1);      

      

    } while (compteur<500);

    printf("\n fin de l'écriture \n");

    //read(fd, data_read, Taille);

    close(fd);

    return 0;

    }

Are the lines as ioctl(fd, CMD_PPI_LINELEN, CFG_PPI_DATALEN_8);  usefull when we want to send datas?

Did I forget something ?

Moreover, when I execute a second time the program, I can see:kernel panic: Unable to attach Blackfin Error Interrupt. I found that my program stopped in the fonction "wait_event_interruptible" of the ppidriver.

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2008-06-17 19:21:34     Re: problems with ppi

Mike Frysinger (UNITED STATES)

Message: 57434   

what do you mean "can't visualize anything on PPI's pins with a probe" ?  you said you're seeing the Tx pin wiggle ...

what toolchain/kernel version are you using ?

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2008-06-18 04:48:55     Re: problems with ppi

tom R (FRANCE)

Message: 57500   

Hi! Thank you for having answered me!

I just want to see each PPI(0-15) signal with an oscilloscope. There is nothing connected to my board.

When the program begin, I can't see any information on signals PPI100-PPI15. All I have is a signal visible

on port Tx0 which is corresponding to nothing.

I am working on the uClinux-dist-2008R1-RC8 and the toolchain version esvn 0.6.12. I would know before if the

IOCTLs configuration are good, and why there is a Kernel panic error when I execute the program a second time.

(not syncing:Unable to attach Blackfin Error Interrupt)