Code:

#define USB_CFG_HAVE_INTRIN_ENDPOINT    1

Code:

static uchar    dataBuffer[4];

int main(void) {
  newMeas = 0;
  hardware_init(); 
  uchar i = 0;
  usbDeviceDisconnect();
  while(--i)         /* fake USB disconnect for > 250 ms */
        _delay_ms(1);
  usbDeviceConnect();
  usbInit();
  sei();
  
  while(1)
  {
   usbPoll();
   if(newMeas && usbInterruptIsReady())  {
     dataBuffer[0] = 5;
     dataBuffer[1] = 5;
     usbSetInterrupt(dataBuffer, 2);
     newMeas = 0;
   }
  }
}

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <usb.h>        
#include "opendevice.h"

struct usb_bus *busses;

usb_dev_handle *find_sensor(void) {
  struct usb_bus *bus;
  char Manufacturer[256], Product[256];
  struct usb_device *dev;
  struct usb_dev_handle *devh = NULL;

  usb_init();
  usb_find_busses();
  usb_find_devices();
  busses = usb_get_busses();

  for(bus = busses; bus; bus = bus->next) {
    for(dev = bus->devices; dev; dev = dev->next) {
      if(dev->descriptor.idVendor == 0x16C0 &&
    dev->descriptor.idProduct == 0x05DC) {
   devh = usb_open(dev);
   if(!devh) {
     perror("usb_open");
     goto xit;
   }
   if(usb_get_string_simple(devh, dev->descriptor.iManufacturer,
             Manufacturer, 255) < 0) {
     perror("usb_get_string_simple(iManufacturer)");
     goto xit;
   }
   if(usb_get_string_simple(devh, dev->descriptor.iProduct, Product,
             255) < 0) {
     perror("usb_get_string_simple(iProduct)");
     goto xit;
   }
   printf("Found %s %s\n",Manufacturer,Product);

     if(usb_set_configuration(devh, 1) < 0) {
       perror("usb_set_configuration"); exit(1);
     }
     if(usb_claim_interface(devh, 0) < 0) {
       perror("usb_claim_interface"); exit(1);
     }
     if((dev->config->interface->altsetting->endpoint->bmAttributes &
         USB_ENDPOINT_TYPE_MASK) != USB_ENDPOINT_TYPE_INTERRUPT) {
       fprintf(stderr, "Endpoint 1 is not an interrupt endpoint\n");
       goto xit;
     }
     return devh;
      }
    xit:
      if(devh) {
   usb_release_interface(devh, 0);
   usb_close(devh);
   devh = NULL;
      }
    }
  }
  return NULL;
}

void close_sensor(usb_dev_handle *devh) {
  if(devh) {
    usb_release_interface(devh, 0);
    usb_close(devh);
  }
}

int main(int argc, char **argv)
{
usb_dev_handle *devh;
  int len;
  char                buffer[4];

  if(!(devh = find_sensor())) {
    fprintf(stderr, "No module found\n");
    exit(1);
  }

  printf("stream begin\n");
  len = usb_interrupt_read(devh, 1, buffer, sizeof(buffer), 3000);
  if(len < 0){
    fprintf(stderr, "USB error: %s\n", usb_strerror());
  }else{
    printf("Value is %u\n", (buffer[0]<<8 | buffer[1])&0xff);
  }
  printf("stream end\n");
close_sensor(devh);
    return 0;
}

Code:

Found A.Mejnertsen PowerMeas
stream
<---3 sec wait--->
USB error: No error
stream end