Call the USB task functions when we are busy-waiting on something

USBCAS/fmtx.c

@@ -58,7 +58,7 @@ uint8_t fmtx_send_byte(uint8_t d)
 void fmtx_drain(void)
 {
 	while (!(UCSR1A & (1 << TXC1)))
-		;
+		do_usb_task();
 }
 
 /*

USBCAS/usbcas.c

@@ -108,6 +108,16 @@ static void update_modem_status(USB_ClassInfo_CDC_Device_t* const CDCInterfaceIn
 	}
 }
 
+/* This is called in the main loop, but also any time we are waiting on something... */
+void do_usb_task(void)
+{
+	/* Update modem flags if needed */
+	update_modem_status(&VirtualSerial_CDC_Interface, false);
+
+	CDC_Device_USBTask(&VirtualSerial_CDC_Interface);
+	USB_USBTask();
+}
+
 /** Main program entry point. This routine contains the overall program flow, including initial
  *  setup of all components and the main program loop.
  */
@@ -170,11 +180,7 @@ int main(void)
 			tx_left = fmtx_send_byte(RingBuffer_Remove(&USBtoCAS_Buffer));
 		}
 
-		/* Update modem flags if needed */
-		update_modem_status(&VirtualSerial_CDC_Interface, false);
-
-		CDC_Device_USBTask(&VirtualSerial_CDC_Interface);
-		USB_USBTask();
+		do_usb_task();
 	}
 }
 

USBCAS/usbcas.h

@@ -52,6 +52,7 @@
 
 /* Function Prototypes: */
 void SetupHardware(void);
+void do_usb_task(void);
 
 void EVENT_USB_Device_Connect(void);
 void EVENT_USB_Device_Disconnect(void);