ESP_XFER_ACTIVE
if (esc->sc_flags & ESP_XFER_ACTIVE) {
esc->sc_flags &= ~ESP_XFER_ACTIVE;
if ((esc->sc_flags & ESP_XFER_ACTIVE) == 0) {
esc->sc_flags &= ~ESP_XFER_ACTIVE;
esc->sc_flags &= ~ESP_XFER_ACTIVE;
esc->sc_flags |= ESP_XFER_ACTIVE;
return esc->sc_flags & ESP_XFER_ACTIVE;