+ /*
+ * If the IBN interrupt is not disabled, clearing
+ * does not work. See AN78446, 6.2.
+ */
+ BYTE ibnsave = IBNIE;
+ IBNIE = 0;
+ CLEAR_USBINT();
+
+ /*
+ * If the host sent the START command, start the GPIF
+ * engine. The host will repeat the BULK IN in the next
+ * microframe.
+ */
+ if ((IBNIRQ & bmEP2IBN) && (gpif_acquiring == PREPARED)) {
+ ledcounter = 1;
+ LED_OFF();
+ gpif_acquisition_start();
+ }
+
+ /* Clear IBN flags for all EPs. */
+ IBNIRQ = 0xff;
+
+ NAKIRQ = bmIBN;
+ SYNCDELAY();
+
+ IBNIE = ibnsave;
+ SYNCDELAY();