Dear All,

I have a problem when testing the V792N 16 CH QDC with the V1718 VME-USB 
Bridge on Scientific Linux 5.1 i386 (kernel 2.6.18-53.1.21.e15).

The problem is that the V792N does not response normally after a few minutes 
of continuous polling and readout of data. It seems like the V792N is hanged 
and a hardware reset of the VME system is required to bring it working again. 
If I do not poll for DREADY first and directly read the Output Buffer 
continuously, the system can work properly.

I have worked on this problem many days but I cannot find any clues to solve 
it. I have tried to use the CAENVMEDemo program (with some modifications) to 
do the same thing (polling and readout) and it works fine. CAEN technical 
support also doesn't know why the VME system is hanged. I think it might be a 
problem of MIDAS itself. I have tried with MIDAS revision 4132 and the trunk 
version, but the problem is still there. Is there any parameter in MIDAS 
(buffer size etc?) which may cause this problem? I have attached my frontend 
code and drivers for your reference.

Thank you for your kind attention.

Best Regards,
Jimmy

/********************************************************************

  Name:         v1718.c
  Created by:   Jimmy Ngai

  Contents:     Midas VME standard (MVMESTD) layer for CAEN V1718
                VME-USB2.0 Bridge using CAENVMElib Linux library

  Based on sis3100.c by Stefan Ritt

  $Id: $

\********************************************************************/

#ifdef __linux__
#ifndef OS_LINUX
#define OS_LINUX
#endif
#endif

#ifdef OS_LINUX

#define _GNU_SOURCE
#include <stdlib.h>
#include <stdio.h>

#include "CAENVMElib.h"

#endif // OS_LINUX

#include "mvmestd.h"

/*------------------------------------------------------------------*/

int mvme_open(MVME_INTERFACE **vme, int idx)
{
   *vme = (MVME_INTERFACE *) malloc(sizeof(MVME_INTERFACE));
   if (*vme == NULL)
      return MVME_NO_MEM;

   memset(*vme, 0, sizeof(MVME_INTERFACE));

   /* open VME */
   if (CAENVME_Init(cvV1718, 0, idx, &(*vme)->handle) != cvSuccess)
      return MVME_NO_INTERFACE;

   /* default values */
   (*vme)->am        = MVME_AM_DEFAULT;
   (*vme)->dmode     = MVME_DMODE_D32;
   (*vme)->blt_mode  = MVME_BLT_NONE;
   (*vme)->table     = NULL; // not used

   return MVME_SUCCESS;
}

/*------------------------------------------------------------------*/

int mvme_close(MVME_INTERFACE *vme)
{
   CAENVME_End(vme->handle);

   return MVME_SUCCESS;
}

/*------------------------------------------------------------------*/

int mvme_sysreset(MVME_INTERFACE *vme)
{
   CAENVME_SystemReset(vme->handle);

   return MVME_SUCCESS;
}

/*------------------------------------------------------------------*/

int mvme_write(MVME_INTERFACE *vme, mvme_addr_t vme_addr, void *src, mvme_size_t n_bytes)
{
   mvme_size_t n;
   DWORD data;
   int status=0;
   int hvme;
   hvme = vme->handle;

   if (n_bytes <= 4) {
      data = n = 0;
      memcpy(&data, src, n_bytes);

      /* D8 */
      if (vme->dmode == MVME_DMODE_D8)
         status = CAENVME_WriteCycle(hvme, vme_addr, &data, vme->am, cvD8);
      /* D16 */
      else if (vme->dmode == MVME_DMODE_D16)
         status = CAENVME_WriteCycle(hvme, vme_addr, &data, vme->am, cvD16);
      /* D32 */
      else if (vme->dmode == MVME_DMODE_D32)
         status = CAENVME_WriteCycle(hvme, vme_addr, &data, vme->am, cvD32);
      
      if (status == cvSuccess)
         n = n_bytes;
      else
         n = 0;
   } else {

      /* D32 BLT */
      if (vme->blt_mode == MVME_BLT_BLT32)
         status |= CAENVME_BLTWriteCycle(hvme, vme_addr, src, n_bytes, vme->am, cvD32, &n);
      /* D64 MBLT */
      else if (vme->blt_mode == MVME_BLT_MBLT64)
         status |= CAENVME_MBLTWriteCycle(hvme, vme_addr, src, n_bytes, vme->am, &n);

      if (status != cvSuccess)
         n = 0;
   }

   return n;
}

/*------------------------------------------------------------------*/

int mvme_write_value(MVME_INTERFACE *vme, mvme_addr_t vme_addr, unsigned int value)
{
   mvme_size_t n;
   int status=0;
   int hvme;
   hvme = vme->handle;

   if (vme->dmode == MVME_DMODE_D8)
      n = 1;
   else if (vme->dmode == MVME_DMODE_D16)
      n = 2;
   else
      n = 4;

   /* D8 */
   if (vme->dmode == MVME_DMODE_D8)
      status = CAENVME_WriteCycle(hvme, vme_addr, &value, vme->am, cvD8);
   /* D16 */
   else if (vme->dmode == MVME_DMODE_D16)
      status = CAENVME_WriteCycle(hvme, vme_addr, &value, vme->am, cvD16);
   /* D32 */
   else if (vme->dmode == MVME_DMODE_D32)
      status = CAENVME_WriteCycle(hvme, vme_addr, &value, vme->am, cvD32);

   if (status != cvSuccess)
      n = 0;

   return n;
}

/*------------------------------------------------------------------*/

int mvme_read(MVME_INTERFACE *vme, void *dst, mvme_addr_t vme_addr, mvme_size_t n_bytes)
{
   mvme_size_t i, n;
   DWORD data;
   int status=0, cfifo;
   int hvme;
   hvme = vme->handle;

   if (n_bytes <= 4) {
      data = 0;

      /* D8 */
      if (vme->dmode == MVME_DMODE_D8)
         status = CAENVME_ReadCycle(hvme, vme_addr, &data, vme->am, cvD8);
      /* D16 */
      else if (vme->dmode == MVME_DMODE_D16)
         status = CAENVME_ReadCycle(hvme, vme_addr, &data, vme->am, cvD16);
      /* D32 */
      else if (vme->dmode == MVME_DMODE_D32)
         status = CAENVME_ReadCycle(hvme, vme_addr, &data, vme->am, cvD32);
      
      memcpy(dst, &data, n_bytes);
      if (status == cvSuccess)
         n = n_bytes;
      else
         n = 0;

   } else {

      n = 0;

      /* normal I/O */
      if (vme->blt_mode == MVME_BLT_NONE) {
         for (i=0 ; i<n_bytes ; i++)
            status = CAENVME_ReadCycle(hvme, vme_addr, dst+i, vme->am, cvD8);
         n = n_bytes;
      /* D32 BLT */
      } else if (vme->blt_mode == MVME_BLT_BLT32)
         status |= CAENVME_BLTReadCycle(hvme, vme_addr, dst, n_bytes, vme->am, cvD32, &n);
      /* D32 FIFO BLT */
      else if (vme->blt_mode == MVME_BLT_BLT32FIFO) {
         CAENVME_GetFIFOMode(hvme, &cfifo);
         status = CAENVME_SetFIFOMode(hvme, 1);
         status |= CAENVME_BLTReadCycle(hvme, vme_addr, dst, n_bytes, vme->am, cvD32, &n);
         CAENVME_SetFIFOMode(hvme, cfifo);
      /* D64 MBLT */
      } else if (vme->blt_mode == MVME_BLT_MBLT64)
         status |= CAENVME_MBLTReadCycle(hvme, vme_addr, dst, n_bytes, vme->am, &n);
      /* D64 FIFO MBLT */
      else if (vme->blt_mode == MVME_BLT_MBLT64FIFO) {
         CAENVME_GetFIFOMode(hvme, &cfifo);
         status = CAENVME_SetFIFOMode(hvme, 1);
         status |= CAENVME_MBLTReadCycle(hvme, vme_addr, dst, n_bytes, vme->am, &n);
         CAENVME_SetFIFOMode(hvme, cfifo);
      }

      if (status != cvSuccess)
         n = 0;
   }

   return n;
}

/*------------------------------------------------------------------*/

unsigned int mvme_read_value(MVME_INTERFACE *vme, mvme_addr_t vme_addr)
{
   unsigned int data;
   int status=0;
   int hvme;
   hvme = vme->handle;

   data = 0;

   /* D8 */
   if (vme->dmode == MVME_DMODE_D8)
      status = CAENVME_ReadCycle(hvme, vme_addr, &data, vme->am, cvD8);
   /* D16 */
   else if (vme->dmode == MVME_DMODE_D16)
      status = CAENVME_ReadCycle(hvme, vme_addr, &data, vme->am, cvD16);
   /* D32 */
   else if (vme->dmode == MVME_DMODE_D32)
      status = CAENVME_ReadCycle(hvme, vme_addr, &data, vme->am, cvD32);

   return data;
}

/*------------------------------------------------------------------*/

int mvme_set_am(MVME_INTERFACE *vme, int am)
{
   vme->am = am;
   return MVME_SUCCESS;
}

/*------------------------------------------------------------------*/

int mvme_get_am(MVME_INTERFACE *vme, int *am)
{
   *am = vme->am;
   return MVME_SUCCESS;
}

/*------------------------------------------------------------------*/

int mvme_set_dmode(MVME_INTERFACE *vme, int dmode)
{
   vme->dmode = dmode;
   return MVME_SUCCESS;
}

/*------------------------------------------------------------------*/

int mvme_get_dmode(MVME_INTERFACE *vme, int *dmode)
{
   *dmode = vme->dmode;
   return MVME_SUCCESS;
}

/*------------------------------------------------------------------*/

int mvme_set_blt(MVME_INTERFACE *vme, int mode)
{
   vme->blt_mode = mode;
   return MVME_SUCCESS;
}

/*------------------------------------------------------------------*/

int mvme_get_blt(MVME_INTERFACE *vme, int *mode)
{
   *mode = vme->blt_mode;
   return MVME_SUCCESS;
}