/* Managed underflow event of IN packet on control endpoint.  */
static void udd_ctrl_underflow(void)
/* Managed underflow event of IN packet on control endpoint.  */
static void udd_ctrl_underflow(void)
{
	if (Is_udd_out_received(0))
		return;
	if (UDD_EPCTRL_DATA_OUT == udd_ep_control_state) {
		udd_ctrl_send_zlp_in();
	} else if (UDD_EPCTRL_HANDSHAKE_WAIT_OUT_ZLP == udd_ep_control_state) {
		udd_enable_stall_handshake(0);
	}
}