- CDC read callback added

class/cdc.c

@@ -72,6 +72,7 @@ int usb_cdc_process_and_return(USB_CallbackEvent *cbevt) {
                 //MSG("%c\n", cbevt->data[0]);
                 ret = 0;
 
+                usb_cdc_read_callback(cbevt->data, cbevt->size);
                 //usbcore_write(cdcs.ep_assignments.data_ep, cbevt->data, cbevt->size); // echo
             }
             break;
@@ -110,3 +111,9 @@ void usb_cdc_write(const uint8_t * data, uint32_t size) {
         bfifo_push_all(&fifo, data, size);
     }
 }
+
+__attribute__((weak)) void usb_cdc_read_callback(const uint8_t * data, uint32_t size) {
+    (void) data;
+    (void) size;
+    return;
+}