skylarmt/usbscale
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Merge branch 'zero-scale'

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This commit is contained in:
Eric Jiang 2020-06-25 22:49:44 -07:00
commit ac1a13730c
1 changed files with 28 additions and 4 deletions
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32
usbscale.c
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@ -29,6 +29,8 @@ along with this program. If not, see <http://www.gnu.org/licenses/>.
#include <sys/types.h>
#include <stdint.h>
#include <math.h>
#include <errno.h>
#include <string.h>
//
// This program uses libusb-1.0 (not the older libusb-0.1) for USB
@ -47,7 +49,9 @@ along with this program. If not, see <http://www.gnu.org/licenses/>.
//
#include "scales.h"
#define WEIGH_REPORT_SIZE 0x06
// Define the number of bytes long that each type of report is
#define WEIGH_REPORT_SIZE 6
#define CONTROL_REPORT_SIZE 2
//
// **find_scale** takes a libusb device list and finds the first USB device
@ -92,7 +96,7 @@ const char* UNITS[13] = {
// main
// ----
//
int main(void)
int main(int argc, char **argv)
{
libusb_device **devs;
int r; // holds return codes
@ -171,7 +175,28 @@ int main(void)
*/
unsigned char data[WEIGH_REPORT_SIZE];
int len;
len = 0;
int scale_result = -1;
// lowest bit is Enforced Zero Return, second bit is Zero Scale
unsigned char tare_report[] = {0x02, 0x02};
if (argc > 1 && strncmp(argv[1], "zero", 5) == 0) {
r = libusb_interrupt_transfer(
handle,
LIBUSB_ENDPOINT_OUT + 2, // direction=host to device, type=standard, recipient=device
tare_report,
CONTROL_REPORT_SIZE,
&len,
10000
);
if (r != 0) {
fprintf(stderr, "errno=%s r=%d (%s) transferred %d bytes\n", strerror(errno), r, libusb_error_name(r), len);
} else {
fprintf(stderr, "tared\n");
}
}
//
// For some reason, we get old data the first time, so let's just get that
@ -181,8 +206,7 @@ int main(void)
handle,
//bmRequestType => direction: in, type: class,
// recipient: interface
LIBUSB_ENDPOINT_IN | //LIBUSB_REQUEST_TYPE_CLASS |
LIBUSB_RECIPIENT_INTERFACE,
LIBUSB_ENDPOINT_IN + 1,
data,
WEIGH_REPORT_SIZE, // length of data
&len,