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#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <libusb-1.0/libusb.h>
#define VENDOR_ID 0x04d8
#define PRODUCT_ID 0x000a
#define ACM_CTRL_DTR 0x01
#define ACM_CTRL_RTS 0x02
#define TIMEOUT 1000
#define BUF_SIZE 64
// line encoding: 9600 8N1
// 9600 = 0x2580 LE
static unsigned char encoding[] = {0x80, 0x25, 0x00, 0x00, 0x00, 0x00, 0x08};
static struct libusb_device_handle *devh = NULL;
static int ep_in_addr = 0x82;
static int ep_out_addr = 0x02;
// Returns 0 on success
static int
setup(void) {
int res;
res = libusb_init(NULL);
if (res < 0) {
fprintf(stderr, "Error initializing libusb: %s\n", libusb_error_name(res));
return -1;
}
libusb_set_debug(NULL, 3);
devh = libusb_open_device_with_vid_pid(NULL, VENDOR_ID, PRODUCT_ID);
if (!devh) {
fprintf(stderr, "Error finding USB device\n");
return -1;
}
for (int ifNum = 0; ifNum < 2; ifNum++) {
if (libusb_kernel_driver_active(devh, ifNum)) {
libusb_detach_kernel_driver(devh, ifNum);
}
res = libusb_claim_interface(devh, ifNum);
if (res < 0) {
fprintf(stderr, "error claiming interface: %s\n", libusb_error_name(res));
return -1;
}
}
res = libusb_control_transfer(devh, 0x21, 0x22, ACM_CTRL_DTR | ACM_CTRL_RTS, 0, NULL, 0, 0);
if (res < 0) {
fprintf(stderr, "Error during control transfer: %s\n", libusb_error_name(res));
return -1;
}
res = libusb_control_transfer(devh, 0x21, 0x20, 0, 0, encoding, sizeof(encoding), 0);
if (res < 0) {
fprintf(stderr, "Error during control transfer: %s\n", libusb_error_name(res));
return -1;
}
return 0;
}
static void
teardown(void) {
if (devh) {
libusb_close(devh);
}
libusb_exit(NULL);
}
// Send bytes to USB
static void
txChars(unsigned char *data, int n) {
int actualLen, res;
actualLen = 0;
while (actualLen < n) {
res = libusb_bulk_transfer(devh, ep_out_addr, data, n, &actualLen, TIMEOUT);
if (res == LIBUSB_ERROR_TIMEOUT) {
printf("Timeout (%d)\n", actualLen);
} else if (res < 0) {
fprintf(stderr, "Error sending data\n");
}
assert(actualLen <= n);
n -= actualLen;
data += actualLen;
}
}
// Read data from USB
// Returns number of bytes read, or -1 on error
static int
rxChars(unsigned char *data, int size) {
int res, actualLen;
res = libusb_bulk_transfer(devh, ep_in_addr, data, size, &actualLen, TIMEOUT);
if (res == LIBUSB_ERROR_TIMEOUT) {
fprintf(stderr, "Timeout\n");
return -1;
} else if (res < 0) {
fprintf(stderr, "Error receiving data\n");
return -1;
}
return actualLen;
}
// Get line from stdin
// Includes '\n'
// Returns number of chars prior to NUL, or EOF on end of file or error
static int
scanline(char *buf, size_t size) {
int c, n;
c = '\0';
n = 0;
while (n+1 < size) {
c = getchar();
if (c == EOF) {
break;
}
buf[n++] = c;
if (c == '\n') {
break;
}
}
if (size > 0) {
buf[n] = '\0';
}
return ((c == EOF) && (n < 1)) ? EOF : n;
}
static void
sendCommand(void) {
unsigned char buf[BUF_SIZE];
int len;
while ((len = scanline(buf, sizeof(buf))) != EOF) {
txChars(buf, len);
if (len > 0 && buf[len-1] == '\n') {
break;
}
}
}
static void
printResponse(void) {
unsigned char buf[BUF_SIZE];
int len;
while ((len = rxChars(buf, sizeof(buf)-1)) >= 0) {
buf[len] = '\0';
printf("%s", buf);
if (buf[len] == '\n') {
return;
}
}
}
int
main(int argc, char *argv[]) {
int res;
if ((res = setup()) != 0) {
teardown();
return res;
}
for (;;) {
sendCommand();
printResponse();
}
libusb_release_interface(devh, 0);
teardown();
return 0;
}
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