USB cdc stdout stream

lib/Descriptors.h

@@ -55,7 +55,7 @@
 #define CDC_NOTIFICATION_EPSIZE 8
 
 /** Size in bytes of the CDC data IN and OUT endpoints. */
-#define CDC_TXRX_EPSIZE 16
+#define CDC_TXRX_EPSIZE 64
 
 /* Type Defines: */
 /** Type define for the device configuration descriptor structure. This must be defined in the

src/main.cpp

@@ -10,6 +10,7 @@
 #include "pins.h"
 #include <avr/interrupt.h>
 #include <util/delay.h>
+#include <stdio.h>
 
 #include "modules/buttons.h"
 #include "modules/finda.h"

src/modules/usb_cdc.cpp

@@ -8,6 +8,12 @@ extern "C" {
 #include "Descriptors.h"
 #include "lufa/LUFA/Drivers/USB/USB.h"
 
+
+/** Standard file stream for the CDC interface when set up, so that the virtual CDC COM port can be
+ *  used like any regular character stream in the C APIs.
+ */
+static FILE USBSerialStream;
+
 /** LUFA CDC Class driver interface configuration and state information. This structure is
  *  passed to all CDC Class driver functions, so that multiple instances of the same class
  *  within a device can be differentiated from one another.
@@ -104,10 +110,16 @@ CDC cdc;
 
 void CDC::Init() {
     USB_Init();
+
+    /* Create a regular character stream for the interface so that it can be used with the stdio.h functions */
+	CDC_Device_CreateStream(&VirtualSerial_CDC_Interface, &USBSerialStream);
+    stdout = &USBSerialStream;
 }
 
 void CDC::Step() {
+    /* Must throw away unused bytes from the host, or it will lock up while waiting for the device */
     CDC_Device_ReceiveByte(&VirtualSerial_CDC_Interface);
+
     CDC_Device_USBTask(&VirtualSerial_CDC_Interface);
     USB_USBTask();
 }