Support F_CPU < 20 MHz with USB disabled

teensy3/usb_desc.c

  * SOFTWARE.
  */
 
+#if F_CPU >= 20000000
+
 #include "usb_desc.h"
 #include "usb_names.h"
 #include "mk20dx128.h"
 
 
 
-
+#endif // F_CPU >= 20 MHz

teensy3/usb_desc.h

 #ifndef _usb_desc_h_
 #define _usb_desc_h_
 
+#if F_CPU >= 20000000
+
 // This header is NOT meant to be included when compiling
 // user sketches in Arduino.  The low-level functions
 // provided by usb_dev.c are meant to be called only by
 extern const usb_descriptor_list_t usb_descriptor_list[];
 
 
+#endif // F_CPU >= 20 MHz
+
 #endif

teensy3/usb_dev.c

  * SOFTWARE.
  */
 
+#if F_CPU >= 20000000
+
 #include "mk20dx128.h"
 //#include "HardwareSerial.h"
 #include "usb_dev.h"
 }
 
 
+#else // F_CPU < 20 MHz
+
+void usb_init(void)
+{
+}
 
+#endif // F_CPU >= 20 MHz

teensy3/usb_dev.h

 #ifndef _usb_dev_h_
 #define _usb_dev_h_
 
+#if F_CPU >= 20000000
+
 // This header is NOT meant to be included when compiling
 // user sketches in Arduino.  The low-level functions
 // provided by usb_dev.c are meant to be called only by
 #endif
 
 
+#endif // F_CPU >= 20 MHz
 
 #endif

teensy3/usb_inst.cpp

 
 #include "WProgram.h"
 
+#if F_CPU >= 20000000
+
 #ifdef USB_SERIAL
 usb_serial_class Serial;
 #endif
 usb_seremu_class Serial;
 #endif
 
+
+#else // F_CPU < 20 MHz
+
+#if defined(USB_SERIAL) || defined(USB_SERIAL_HID)
+usb_serial_class Serial;
+#else
+usb_seremu_class Serial;
+#endif
+
+#endif // F_CPU

teensy3/usb_mem.c

  * SOFTWARE.
  */
 
+#if F_CPU >= 20000000
+
 #include "mk20dx128.h"
 //#include "HardwareSerial.h"
 #include "usb_dev.h"
 	//serial_print("\n");
 }
 
+#endif // F_CPU >= 20 MHz

teensy3/usb_seremu.c

  * SOFTWARE.
  */
 
+#if F_CPU >= 20000000
+
 //#include "mk20dx128.h"
 #include "usb_dev.h"
 #include "usb_seremu.h"
 }
 
 #endif // SEREMU_INTERFACE
+
+#endif // F_CPU >= 20 MHz

teensy3/usb_seremu.h

 
 #include <inttypes.h>
 
+#if F_CPU >= 20000000
+
 // C language implementation
 #ifdef __cplusplus
 extern "C" {
 }
 #endif
 
-
 // C++ interface
 #ifdef __cplusplus
 #include "Stream.h"
         uint8_t rts(void) { return 1; }
         operator bool() { return usb_configuration; }
 };
-
 extern usb_seremu_class Serial;
+#endif // __cplusplus
+
 
+
+#else  // F_CPU < 20 MHz
+
+// Allow Arduino programs using Serial to compile, but Serial will do nothing.
+#ifdef __cplusplus
+#include "Stream.h"
+class usb_seremu_class : public Stream
+{
+public:
+	void begin(long) { };
+	void end() { };
+	virtual int available() { return 0; }
+	virtual int read() { return -1; }
+	virtual int peek() { return -1; }
+	virtual void flush() { }
+	virtual size_t write(uint8_t c) { return 1; }
+	virtual size_t write(const uint8_t *buffer, size_t size) { return size; }
+	size_t write(unsigned long n) { return 1; }
+	size_t write(long n) { return 1; }
+	size_t write(unsigned int n) { return 1; }
+	size_t write(int n) { return 1; }
+	using Print::write;
+	void send_now(void) { }
+	uint32_t baud(void) { return 0; }
+	uint8_t stopbits(void) { return 1; }
+	uint8_t paritytype(void) { return 0; }
+	uint8_t numbits(void) { return 8; }
+	uint8_t dtr(void) { return 1; }
+	uint8_t rts(void) { return 1; }
+	operator bool() { return true; }
+};
+
+extern usb_seremu_class Serial;
 #endif // __cplusplus
 
+
+#endif // F_CPU >= 20 MHz
+
 #endif // USB_HID
+
 #endif // USBseremu_h_

teensy3/usb_serial.h

 
 #include <inttypes.h>
 
+#if F_CPU >= 20000000
+
 // C language implementation
 #ifdef __cplusplus
 extern "C" {
 #define USB_SERIAL_DTR  0x01
 #define USB_SERIAL_RTS  0x02
 
-
 // C++ interface
 #ifdef __cplusplus
 #include "Stream.h"
 	}
 
 };
-
 extern usb_serial_class Serial;
+#endif // __cplusplus
+
 
+#else  // F_CPU < 20 MHz
+
+// Allow Arduino programs using Serial to compile, but Serial will do nothing.
+#ifdef __cplusplus
+#include "Stream.h"
+class usb_serial_class : public Stream
+{
+public:
+        void begin(long) { };
+        void end() { };
+        virtual int available() { return 0; }
+        virtual int read() { return -1; }
+        virtual int peek() { return -1; }
+        virtual void flush() { }
+        virtual size_t write(uint8_t c) { return 1; }
+        virtual size_t write(const uint8_t *buffer, size_t size) { return size; }
+	size_t write(unsigned long n) { return 1; }
+	size_t write(long n) { return 1; }
+	size_t write(unsigned int n) { return 1; }
+	size_t write(int n) { return 1; }
+	using Print::write;
+        void send_now(void) { }
+        uint32_t baud(void) { return 0; }
+        uint8_t stopbits(void) { return 1; }
+        uint8_t paritytype(void) { return 0; }
+        uint8_t numbits(void) { return 8; }
+        uint8_t dtr(void) { return 1; }
+        uint8_t rts(void) { return 1; }
+        operator bool() { return true; }
+};
+
+extern usb_serial_class Serial;
 #endif // __cplusplus
 
+#endif // F_CPU
+
 #endif // USB_SERIAL || USB_SERIAL_HID
+
 #endif // USBserial_h_