Do not send if USB is not active

main.c

@@ -895,6 +895,7 @@ VNA_SHELL_FUNCTION(cmd_capture)
 
 void send_region(const char *t, int x, int y, int w, int h)
 {
+  if (SDU1.config->usbp->state == USB_ACTIVE) {
     shell_printf(t);
     struct {
       char new_str[2];
@@ -905,12 +906,17 @@ void send_region(const char *t, int x, int y, int w, int h)
     } region={"\r\n", x,y,w,h};
     streamWrite(shell_stream, (void*)&region, sizeof(region));
   }
+  else
+    auto_capture = false;
+}
 
 void send_buffer(uint8_t * buf, int s)
 {
+  if (SDU1.config->usbp->state == USB_ACTIVE) {
     streamWrite(shell_stream, (void*) buf, s);
     streamWrite(shell_stream, (void*)"ch> \r\n", 6);
   }
+}
 
 #if 0
 VNA_SHELL_FUNCTION(cmd_gamma)