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Merge pull request #11 from sanmai/master

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Support for additional scale, fix weight calculation
This commit is contained in:
erjiang 2015-10-26 12:11:31 -07:00
commit 60b6f396ff
2 changed files with 36 additions and 14 deletions
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6
scales.h
View File

@ -12,7 +12,7 @@
//
// **NSCALES** should be kept updated with the length of the list.
//
#define NSCALES 6
#define NSCALES 8
//
// What is the number of the weighing result to show, as the first result may be incorrect (from the previous weighing)
@ -37,5 +37,7 @@ uint16_t scales[NSCALES][2] = {\
// SANFORD Dymo 10 lb USB Postal Scale
{0x6096, 0x0158},
// Fairbanks Scales SCB-R9000
{0x0b67, 0x555e}
{0x0b67, 0x555e},
// Dymo-CoStar Corp. M25 Digital Postal Scale
{0x0922, 0x8004}
};

44
usbscale.c
View File

@ -60,6 +60,12 @@ static libusb_device* find_scale(libusb_device**);
// program should read again (i.e. continue looping).
//
static int print_scale_data(unsigned char*);
//
// take device and fetch bEndpointAddress for the first endpoint
//
uint8_t get_first_endpoint_address(libusb_device* dev);
//
// **UNITS** is an array of all the unit abbreviations as set forth by *HID
// Point of Sale Usage Tables*, version 1.02, by the USB Implementers' Forum.
@ -197,8 +203,7 @@ int main(void)
handle,
//bmRequestType => direction: in, type: class,
// recipient: interface
LIBUSB_ENDPOINT_IN | //LIBUSB_REQUEST_TYPE_CLASS |
LIBUSB_RECIPIENT_INTERFACE,
get_first_endpoint_address(dev),
data,
WEIGH_REPORT_SIZE, // length of data
&len,
@ -276,16 +281,12 @@ static int print_scale_data(unsigned char* dat) {
uint8_t report = dat[0];
uint8_t status = dat[1];
uint8_t unit = dat[2];
uint8_t expt = dat[3];
double weight = (double)(dat[4] + (dat[5] << 8)) / 10;
if(expt != 255 && expt != 0) {
if (expt > 127) {
weight = weight * pow(10, expt-255);
} else {
weight = pow(weight, expt);
}
}
// Accoring to the docs, scaling applied to the data as a base ten exponent
int8_t expt = dat[3];
// convert to machine order at all times
double weight = (double) le16toh(dat[5] << 8 | dat[4]);
// since the expt is signed, we do not need no trickery
weight = weight * pow(10, expt);
//
// The scale's first byte, its "report", is always 3.
@ -418,3 +419,22 @@ static libusb_device* find_scale(libusb_device **devs)
return NULL;
}
uint8_t get_first_endpoint_address(libusb_device* dev)
{
// default value
uint8_t endpoint_address = LIBUSB_ENDPOINT_IN | LIBUSB_RECIPIENT_INTERFACE; //| LIBUSB_RECIPIENT_ENDPOINT;
struct libusb_config_descriptor *config;
int r = libusb_get_config_descriptor(dev, 0, &config);
if (r == 0) {
// assuming we have only one endpoint
endpoint_address = config->interface[0].altsetting[0].endpoint[0].bEndpointAddress;
libusb_free_config_descriptor(config);
}
#ifdef DEBUG
printf("bEndpointAddress 0x%02x\n", endpoint_address);
#endif
return endpoint_address;
}