ESP_XFER_LOADED
if (esc->sc_flags & ESP_XFER_LOADED) {
esc->sc_flags &= ~ESP_XFER_LOADED;
esc->sc_flags &= ~ESP_XFER_LOADED;
if (esc->sc_flags & ESP_XFER_LOADED) {
esc->sc_flags &= ~ESP_XFER_LOADED;
esc->sc_flags |= ESP_XFER_LOADED | (datain ? ESP_XFER_READ : 0);