mirror of
https://github.com/erjiang/usbscale.git
synced 2025-06-28 00:50:59 -06:00
Try using every scale found
This commit is contained in:
Eric Jiang
parent
1d3a7f5ea5
commit
a26fd9eb55
2
Makefile
2
Makefile
@ -1,5 +1,5 @@
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LDLIBS=-lm -lusb-1.0
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CFLAGS=-Os -Wall
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CFLAGS=-Os -Wall -Wextra
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DOCCO=docco
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usbscale: usbscale.c scales.h
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362
usbscale.c
362
usbscale.c
@ -25,6 +25,8 @@ GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <stdbool.h>
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#include <stdio.h>
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#include <sys/types.h>
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#include <stdint.h>
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@ -54,10 +56,10 @@ along with this program. If not, see <http://www.gnu.org/licenses/>.
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#define CONTROL_REPORT_SIZE 2
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//
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// **find_scale** takes a libusb device list and finds the first USB device
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// **is_scale** takes a libusb device list and finds the first USB device
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// that matches a device listed in scales.h.
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//
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static libusb_device* find_scale(libusb_device**);
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static bool is_scale(libusb_device*);
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//
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// **print_scale_data** takes the 6-byte output from the scale and interprets
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// it, printing out the result to the screen. It also returns a 1 if the
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@ -103,6 +105,7 @@ int main(int argc, char **argv)
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ssize_t cnt;
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libusb_device* dev;
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libusb_device_handle* handle;
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bool found_scale = false;
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int weigh_count = WEIGH_COUNT -1;
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@ -127,154 +130,167 @@ int main(int argc, char **argv)
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return (int) cnt;
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//
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// Once we have the list, we use **find_scale** to loop through and match
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// every device against the scales.h list. **find_scale** will return the
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// Once we have the list, we use **is_scale** to loop through and match
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// every device against the scales.h list. **is_scale** will return the
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// first device that matches, or 0 if none of them matched.
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//
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dev = find_scale(devs);
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if(dev == 0) {
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fprintf(stderr, "No USB scale found on this computer.\n");
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return -1;
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}
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//
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// Once we have a pointer to the USB scale in question, we open it.
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//
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r = libusb_open(dev, &handle);
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//
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// Note that this requires that we have permission to access this device.
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// If you get the "permission denied" error, check your udev rules.
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//
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if(r < 0) {
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if(r == LIBUSB_ERROR_ACCESS) {
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fprintf(stderr, "Permission denied to scale.\n");
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int i = 0;
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while ((dev = devs[i++]) != NULL) {
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if (!is_scale(dev)) {
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continue;
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}
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else if(r == LIBUSB_ERROR_NO_DEVICE) {
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fprintf(stderr, "Scale has been disconnected.\n");
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}
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return -1;
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}
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//
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// On Linux, we typically need to detach the kernel driver so that we can
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// handle this USB device. We are a userspace tool, after all.
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//
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#ifdef __linux__
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libusb_detach_kernel_driver(handle, 0);
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#endif
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//
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// Finally, we can claim the interface to this device and begin I/O.
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//
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libusb_claim_interface(handle, 0);
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found_scale = true;
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/*
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* Try to transfer data about status
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*
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* http://rowsandcolumns.blogspot.com/2011/02/read-from-magtek-card-swipe-reader-in.html
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*/
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unsigned char data[WEIGH_REPORT_SIZE];
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int len;
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len = 0;
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int scale_result = -1;
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// lowest bit is Enforced Zero Return, second bit is Zero Scale
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unsigned char tare_report[] = {0x02, 0x02};
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if (argc > 1 && strncmp(argv[1], "zero", 5) == 0) {
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r = libusb_interrupt_transfer(
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handle,
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LIBUSB_ENDPOINT_OUT + 2, // direction=host to device, type=standard, recipient=device
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tare_report,
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CONTROL_REPORT_SIZE,
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&len,
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10000
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);
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if (r != 0) {
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fprintf(stderr, "errno=%s r=%d (%s) transferred %d bytes\n", strerror(errno), r, libusb_error_name(r), len);
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} else {
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fprintf(stderr, "tared\n");
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}
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}
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//
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// For some reason, we get old data the first time, so let's just get that
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// out of the way now. It can't hurt to grab another packet from the scale.
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//
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r = libusb_interrupt_transfer(
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handle,
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//bmRequestType => direction: in, type: class,
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// recipient: interface
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LIBUSB_ENDPOINT_IN + 1,
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data,
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WEIGH_REPORT_SIZE, // length of data
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&len,
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10000 //timeout => 10 sec
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);
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//
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// We read data from the scale in an infinite loop, stopping when
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// **print_scale_data** tells us that it's successfully gotten the weight
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// from the scale, or if the scale or transmissions indicates an error.
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//
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for(;;) {
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//
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// A `libusb_interrupt_transfer` of 6 bytes from the scale is the
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// typical scale data packet, and the usage is laid out in *HID Point
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// of Sale Usage Tables*, version 1.02.
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// Once we have a pointer to the USB scale in question, we open it.
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//
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r = libusb_open(dev, &handle);
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//
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// Note that this requires that we have permission to access this device.
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// If you get the "permission denied" error, check your udev rules.
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//
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if(r < 0) {
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if(r == LIBUSB_ERROR_ACCESS) {
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fprintf(stderr, "Permission denied to scale.\n");
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}
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else if(r == LIBUSB_ERROR_NO_DEVICE) {
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fprintf(stderr, "Scale has been disconnected.\n");
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}
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return -1;
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}
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//
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// On Linux, we typically need to detach the kernel driver so that we can
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// handle this USB device. We are a userspace tool, after all.
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//
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#ifdef __linux__
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libusb_detach_kernel_driver(handle, 0);
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#endif
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//
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// Finally, we can claim the interface to this device and begin I/O.
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//
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libusb_claim_interface(handle, 0);
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/*
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* Try to transfer data about status
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*
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* http://rowsandcolumns.blogspot.com/2011/02/read-from-magtek-card-swipe-reader-in.html
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*/
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unsigned char data[WEIGH_REPORT_SIZE];
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int len;
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len = 0;
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int scale_result = -1;
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// lowest bit is Enforced Zero Return, second bit is Zero Scale
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unsigned char tare_report[] = {0x02, 0x02};
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if (argc > 1 && strncmp(argv[1], "zero", 5) == 0) {
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r = libusb_interrupt_transfer(
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handle,
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LIBUSB_ENDPOINT_OUT + 2, // direction=host to device, type=standard, recipient=device
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tare_report,
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CONTROL_REPORT_SIZE,
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&len,
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10000
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);
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if (r != 0) {
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fprintf(stderr, "errno=%s r=%d (%s) transferred %d bytes\n", strerror(errno), r, libusb_error_name(r), len);
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} else {
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fprintf(stderr, "tared\n");
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}
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}
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//
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// For some reason, we get old data the first time, so let's just get that
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// out of the way now. It can't hurt to grab another packet from the scale.
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//
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r = libusb_interrupt_transfer(
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handle,
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//bmRequestType => direction: in, type: class,
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// recipient: interface
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get_first_endpoint_address(dev),
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LIBUSB_ENDPOINT_IN + 1,
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data,
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WEIGH_REPORT_SIZE, // length of data
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&len,
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10000 //timeout => 10 sec
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);
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//
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// If the data transfer succeeded, then we pass along the data we
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// received to **print_scale_data**.
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// We read data from the scale in an infinite loop, stopping when
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// **print_scale_data** tells us that it's successfully gotten the weight
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// from the scale, or if the scale or transmissions indicates an error.
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//
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if(r == 0) {
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#ifdef DEBUG
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int i;
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for(i = 0; i < WEIGH_REPORT_SIZE; i++) {
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printf("%x\n", data[i]);
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for(;;) {
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//
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// A `libusb_interrupt_transfer` of 6 bytes from the scale is the
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// typical scale data packet, and the usage is laid out in *HID Point
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// of Sale Usage Tables*, version 1.02.
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//
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r = libusb_interrupt_transfer(
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handle,
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//bmRequestType => direction: in, type: class,
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// recipient: interface
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get_first_endpoint_address(dev),
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data,
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WEIGH_REPORT_SIZE, // length of data
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&len,
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10000 //timeout => 10 sec
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);
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//
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// If the data transfer succeeded, then we pass along the data we
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// received to **print_scale_data**.
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//
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if(r == 0) {
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#ifdef DEBUG
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int i;
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for(i = 0; i < WEIGH_REPORT_SIZE; i++) {
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printf("%x\n", data[i]);
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}
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#endif
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if (weigh_count < 1) {
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scale_result = print_scale_data(data);
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if(scale_result != 1)
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break;
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}
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weigh_count--;
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}
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#endif
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if (weigh_count < 1) {
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scale_result = print_scale_data(data);
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if(scale_result != 1)
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break;
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else {
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fprintf(stderr, "Error in USB transfer\n");
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scale_result = -1;
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break;
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}
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weigh_count--;
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}
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else {
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fprintf(stderr, "Error in USB transfer\n");
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scale_result = -1;
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break;
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//
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// At the end, we make sure that we reattach the kernel driver that we
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// detached earlier, close the handle to the device, free the device list
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// that we retrieved, and exit libusb.
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//
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#ifdef __linux__
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libusb_attach_kernel_driver(handle, 0);
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#endif
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libusb_close(handle);
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libusb_free_device_list(devs, 1);
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libusb_exit(NULL);
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//
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// The return code will be 0 for success or -1 for errors (see
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// `libusb_init` above if it's neither 0 nor -1).
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//
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if (scale_result != 0) {
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return scale_result;
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}
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}
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//
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// At the end, we make sure that we reattach the kernel driver that we
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// detached earlier, close the handle to the device, free the device list
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// that we retrieved, and exit libusb.
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// if no scales were found, make sure to show a message
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//
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#ifdef __linux__
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libusb_attach_kernel_driver(handle, 0);
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#endif
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libusb_close(handle);
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libusb_free_device_list(devs, 1);
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libusb_exit(NULL);
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//
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// The return code will be 0 for success or -1 for errors (see
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// `libusb_init` above if it's neither 0 nor -1).
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//
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return scale_result;
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if(!found_scale) {
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fprintf(stderr, "No USB scale found on this computer.\n");
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return -1;
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}
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return 0;
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}
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//
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@ -372,75 +388,65 @@ static int print_scale_data(unsigned char* dat) {
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}
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//
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// find_scale
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// is_scale
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// ----------
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//
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// **find_scale** takes a `libusb_device\*\*` list and loop through it,
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// **is_scale** takes a `libusb_device\*\*` list and loop through it,
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// matching each device's vendor and product IDs to the scales.h list. It
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// return the first matching `libusb_device\*` or 0 if no matching device is
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// found.
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//
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static libusb_device* find_scale(libusb_device **devs)
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static bool is_scale(libusb_device *dev)
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{
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int i = 0;
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libusb_device* dev = 0;
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//
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// Loop through each USB device, and for each device, loop through the
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// scales list to see if it's one of our listed scales.
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//
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while ((dev = devs[i++]) != NULL) {
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struct libusb_device_descriptor desc;
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int r = libusb_get_device_descriptor(dev, &desc);
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if (r < 0) {
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fprintf(stderr, "failed to get device descriptor");
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return NULL;
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}
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int i;
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for (i = 0; i < NSCALES; i++) {
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if(desc.idVendor == scales[i][0] &&
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desc.idProduct == scales[i][1]) {
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/*
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* Debugging data about found scale
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*/
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struct libusb_device_descriptor desc;
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int r = libusb_get_device_descriptor(dev, &desc);
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if (r < 0) {
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fprintf(stderr, "failed to get device descriptor");
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return NULL;
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}
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int i;
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for (i = 0; i < NSCALES; i++) {
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if(desc.idVendor == scales[i][0] &&
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desc.idProduct == scales[i][1]) {
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/*
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* Debugging data about found scale
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*/
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#ifdef DEBUG
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fprintf(stderr,
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"Found scale %04x:%04x (bus %d, device %d)\n",
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desc.idVendor,
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desc.idProduct,
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libusb_get_bus_number(dev),
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libusb_get_device_address(dev));
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fprintf(stderr,
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"Found scale %04x:%04x (bus %d, device %d)\n",
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desc.idVendor,
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desc.idProduct,
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libusb_get_bus_number(dev),
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libusb_get_device_address(dev));
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fprintf(stderr,
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"It has descriptors:\n\tmanufc: %d\n\tprodct: %d\n\tserial: %d\n\tclass: %d\n\tsubclass: %d\n",
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desc.iManufacturer,
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desc.iProduct,
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desc.iSerialNumber,
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desc.bDeviceClass,
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desc.bDeviceSubClass);
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fprintf(stderr,
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"It has descriptors:\n\tmanufc: %d\n\tprodct: %d\n\tserial: %d\n\tclass: %d\n\tsubclass: %d\n",
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desc.iManufacturer,
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desc.iProduct,
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desc.iSerialNumber,
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desc.bDeviceClass,
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desc.bDeviceSubClass);
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/*
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* A char buffer to pull string descriptors in from the device
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*/
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unsigned char string[256];
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libusb_device_handle* hand;
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libusb_open(dev, &hand);
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/*
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* A char buffer to pull string descriptors in from the device
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*/
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unsigned char string[256];
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libusb_device_handle* hand;
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libusb_open(dev, &hand);
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r = libusb_get_string_descriptor_ascii(hand, desc.iManufacturer,
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string, 256);
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fprintf(stderr,
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"Manufacturer: %s\n", string);
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libusb_close(hand);
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r = libusb_get_string_descriptor_ascii(hand, desc.iManufacturer,
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string, 256);
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fprintf(stderr,
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"Manufacturer: %s\n", string);
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libusb_close(hand);
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#endif
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return dev;
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break;
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}
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return true;
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break;
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}
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}
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return NULL;
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return false;
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}
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uint8_t get_first_endpoint_address(libusb_device* dev)
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