usb.h and libusb.

General discussions about V-USB, our firmware-only implementation of a low speed USB device on Atmel's AVR microcontrollers
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usb.h and libusb.

Post by stf92 » Tue Jan 21, 2014 7:17 pm


Code: Select all

#include <usb.h>
#include <stdio.h>
#include <string.h>
unsigned short IDVendor=   0x1384;              /*VID must be changed. */
unsigned short IDProduct=  0x8888;              /*PID must be changed. */


int main(int argc, char **argv)
        usb_dev_handle *d=NULL;
        unsigned char buffer[3];
        int i, mode, ret;
        char string[256];

        if(argc <2)
                printf("give the voltage value.\n");
        i=floor(atof(argv[1])*51) ;
 if(i>255){printf("value must be between 0 and 5V\n"); exit(1);}
ret=usbOpenDevice(&d, IDVendor,IDProduct);
if(ret!=0){printf("usbOpenDevice failed\n"); return 0;}

   ret=usb_control_msg(d, USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_ENDPOINT_IN, mode, i, 0, (char *)buffer, sizeof(buffer), 5000);

//      printf("buffer %d \n", buffer[0]);
        return 0;

This is part of an application program running on linux. Looking for documentation for usb_control_msg(), shown in the last lines above, I first went to /usr/include/usb.h, that is in the #include's (first lines), and the function was there. Looking for the source, I found /usr/src/linux-3.2.29/drivers/usb/core/message.c, where it is defined but, alas, here it has the arguments in different order and they are 9 instead of 8). As the author asks for the libusb library, the logical thing was to look in its sources, which I installed, just now, from the O.S. distribution disks. But here there is no usb_control_msg(), nor even the usb.h file!

So, what should the source for usb.h be?

Note: in usb.h there is declared a function usb_control_msg with the same number and order of parameters as in my source.

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