Experimental Physics and
Industrial Control System

Paweł Plewiński <[email protected]> · Tue, 11 Apr 2017 15:49:01 +0200

Hi,

I've recently written asyn-based device support for a custom device

communicating over PCIe. One of its functions is to periodically

retrieve 4 waveforms from 4 channels, which is done in a separate

thread, from which the callback function is called to notify asyn about

change. I heavily based the code on the AsynPortDriver example.

The driver works, however if the update rate is lower than 1 second,

strange warning appears in the console at the time of every refresh (and

that's only for one of 4 channels), namely:

2017/04/11 15:42:08.682 PIEZO:OSC-CH0-WAVEFORM

devAsynFloat64Array::interruptCallbackInput

\000\000\000\000\000@\205?\000\000\000\000\000\300\202?\000\000\000\000\000\000\204?\000\000\000\000\000\000\204?\000\000\000\000\000\300\202?\000\000\000\000\000\000\204?\000\000\000\000\000@\205?\000\000\000\000\000\000\204?\000\000\000\000\000\300\202?\000\000\000\000\000\000\204?

2017/04/11 15:42:08.682 PIEZO:OSC-CH0-WAVEFORM

devAsynFloat64Array::processCommon, warning, multiple interrupt

callbacks between processing

The parameters passed to the top level constructor are
   : asynPortDriver(portName,
                    4, /* maxAddr */
                    (int)NUM_SCOPE_PARAMS,

 asynInt32Mask | asynFloat64Mask |

asynFloat64ArrayMask | asynEnumMask | asynDrvUserMask, /* Interface mask

*/

 asynInt32Mask | asynFloat64Mask |

asynFloat64ArrayMask | asynEnumMask, /* Interrupt mask */

 ASYN_MULTIDEVICE, /* asynFlags. This driver does

not block and it is not multi-device, so flag is 0 */

                    1, /* Autoconnect */
                    0, /* Default priority */
                    0) /* Default stack size*/

The readback thread code:

void piezoPortDriver::readbackTask(void)
{
   while (1) {
           bool stopped = false;

           lock();
           auto new_data = osc->fetch_data(vtim, vdat);
           unlock();

           if (!stopped)
           {
               lock();
               this->osc_update_trigger();
               unlock();
           }
        callParamCallbacks();

        for (int i = 0; i < 4; i++){

 doCallbacksFloat64Array(vdat[i].data(), vdat[i].size(),

P_OscWaveform, i);

        }
        usleep(100000);
    }
}

The fetch_data method reads four 1000-element double vectors from PCIe.

Could you give me some suggestions what may be wrong?

Regards,
Paweł Plewiński
Department of Microelectronics and Computer Science
Lodz University of Technology

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System