stmhal: Add pyb.have_cdc function to check if USB CDC device is enabled.

stmhal/modpyb.c

@@ -193,6 +193,12 @@ STATIC mp_obj_t pyb_standby(void) {
 
 MP_DEFINE_CONST_FUN_OBJ_0(pyb_standby_obj, pyb_standby);
 
+STATIC mp_obj_t pyb_have_cdc(void ) {
+    return MP_BOOL(usb_vcp_is_connected());
+}
+
+STATIC MP_DEFINE_CONST_FUN_OBJ_0(pyb_have_cdc_obj, pyb_have_cdc);
+
 STATIC mp_obj_t pyb_hid_send_report(mp_obj_t arg) {
     mp_obj_t *items;
     mp_obj_get_array_fixed_n(arg, 4, &items);
@@ -235,6 +241,9 @@ STATIC const mp_map_elem_t pyb_module_globals_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_main), (mp_obj_t)&pyb_main_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_usb_mode), (mp_obj_t)&pyb_usb_mode_obj },
 
+    { MP_OBJ_NEW_QSTR(MP_QSTR_have_cdc), (mp_obj_t)&pyb_have_cdc_obj },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_hid), (mp_obj_t)&pyb_hid_send_report_obj },
+
     { MP_OBJ_NEW_QSTR(MP_QSTR_millis), (mp_obj_t)&pyb_millis_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_delay), (mp_obj_t)&pyb_delay_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_udelay), (mp_obj_t)&pyb_udelay_obj },
@@ -278,8 +287,6 @@ STATIC const mp_map_elem_t pyb_module_globals_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_Accel), (mp_obj_t)&pyb_accel_type },
 #endif
 
-    { MP_OBJ_NEW_QSTR(MP_QSTR_hid), (mp_obj_t)&pyb_hid_send_report_obj },
-
     // input
     { MP_OBJ_NEW_QSTR(MP_QSTR_input), (mp_obj_t)&pyb_input_obj },
 

stmhal/qstrdefsport.h

@@ -25,6 +25,7 @@ Q(read)
 Q(readall)
 Q(readline)
 Q(write)
+Q(have_cdc)
 Q(hid)
 Q(time)
 Q(rng)