Small libusb test program to send querie to a TI-Python module

usb.c

// gcc usb.c `pkg-config --libs --cflags libusb-1.0

#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <libusb.h>

static struct libusb_device_handle *devh = NULL;

static int open_device(void) {
	devh = libusb_open_device_with_vid_pid(NULL, 0x0451, 0xE020);
	return devh ? 0 : -EIO;
}

void DumpHex(const void* data, size_t size) {
	char ascii[17];
	size_t i, j;
	ascii[16] = '\0';
	for (i = 0; i < size; ++i) {
		printf("%02X ", ((unsigned char*)data)[i]);
		if (((unsigned char*)data)[i] >= ' ' && ((unsigned char*)data)[i] <= '~') {
			ascii[i % 16] = ((unsigned char*)data)[i];
		} else {
			ascii[i % 16] = '.';
		}
		if ((i+1) % 8 == 0 || i+1 == size) {
			printf(" ");
			if ((i+1) % 16 == 0) {
				printf("|  %s \n", ascii);
			} else if (i+1 == size) {
				ascii[(i+1) % 16] = '\0';
				if ((i+1) % 16 <= 8) {
					printf(" ");
				}
				for (j = (i+1) % 16; j < 16; ++j) {
					printf("   ");
				}
				printf("|  %s \n", ascii);
			}
		}
	}
}

int main(int argc, char* argv[]) {
  int r;

  r = libusb_init(NULL);
  if (r < 0) {
    fprintf(stderr, "failed to initialise libusb\n");
    exit(1);
  }

  r = open_device();
  if (r < 0) {
    fprintf(stderr, "Could not find/open device\n");
    goto out;
  }

  if(libusb_kernel_driver_active(devh, 2)) {
    r = libusb_detach_kernel_driver(devh, 2);
    if (r < 0) {
      fprintf(stderr, "libusb_detach_kernel_driver error %d\n", r);
      goto out;
    }
    printf("interface detached\n");
  }

  r = libusb_claim_interface(devh, 2);
  if (r < 0) {
    fprintf(stderr, "usb_claim_interface error %d\n", r);
    goto out;
  }
  printf("claimed interface\n");

  // 80 03 06 12																																								lun                   17   18    19   20
  unsigned char req[31] = {0x55,0x53,0x42,0x43, 0x19,0x95,0x48,0x00 ,0x65,0x00,0x00,0x00, 0x80 ,0x03 ,0x06, 0x12,0x00,0x76,0x04,0x65,0x0C,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00};
  //unsigned char req[31] = {0x55,0x53,0x42,0x43,0xC1,0x4A,0x9F,0x00,0x65,0x00,0x00,0x00,0x80,0x03,0x06,0x12,0x00,0x2D,0x02,0x65,0x3C,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00};
  // req[17] = 0x09;
  // req[18] = 0x04;
  // req[19] = 0x65; // Unused ?
  // req[20] = 0x0C;

  //printf("%x\n", req[20] + (req[17] << 8) + (req[18] << 14) + 0x2000);

	//unsigned char req[31] = {0x55 ,0x53 ,0x42 ,0x43 ,0xA1 ,0x43 ,0x1C ,0x00 ,0x24 ,0x00 ,0x00 ,0x00 ,0x80 ,0x02 ,0x06 ,0x12 ,0x00 ,0x00 ,0x00 ,0x24 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00};
  r = libusb_bulk_transfer(devh, 0x04, req, 31, NULL, 1000);
  if (r < 0) {
    fprintf(stderr, "send error %d\n", r);
    goto out;
  }
  printf("send ok\n");

  int nb_read;
  unsigned char read[1024];
  r = libusb_bulk_transfer(devh, 0x83, read, 116, &nb_read, 1000);
  if (r < 0) {
    fprintf(stderr, "read error %d\n", r);
    goto out;
  }
  printf("read ok: %d\n", nb_read);
  DumpHex(read, nb_read);

  r = libusb_bulk_transfer(devh, 0x83, read, 116, &nb_read, 1000);
  if (r < 0) {
    fprintf(stderr, "read error %d\n", r);
    goto out;
  }
  printf("read ok: %d\n", nb_read);
  DumpHex(read, nb_read);

  out:
  	libusb_close(devh);
  	libusb_exit(NULL);
  	return r >= 0 ? r : -r;
}