add initial files from teensy's usb_keyboard_debug.

example.c

@@ -0,0 +1,137 @@
+/* Keyboard example with debug channel, for Teensy USB Development Board
+ * http://www.pjrc.com/teensy/usb_keyboard.html
+ * Copyright (c) 2008 PJRC.COM, LLC
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <avr/io.h>
+#include <avr/pgmspace.h>
+#include <avr/interrupt.h>
+#include <util/delay.h>
+#include "usb_keyboard_debug.h"
+#include "print.h"
+
+#define LED_CONFIG	(DDRD |= (1<<6))
+#define LED_ON		(PORTD &= ~(1<<6))
+#define LED_OFF		(PORTD |= (1<<6))
+#define CPU_PRESCALE(n)	(CLKPR = 0x80, CLKPR = (n))
+
+uint8_t number_keys[10]=
+	{KEY_0,KEY_1,KEY_2,KEY_3,KEY_4,KEY_5,KEY_6,KEY_7,KEY_8,KEY_9};
+
+uint16_t idle_count=0;
+
+int main(void)
+{
+	uint8_t b, d, mask, i, reset_idle;
+	uint8_t b_prev=0xFF, d_prev=0xFF;
+
+	// set for 16 MHz clock
+	CPU_PRESCALE(0);
+
+	// Configure all port B and port D pins as inputs with pullup resistors.
+	// See the "Using I/O Pins" page for details.
+	// http://www.pjrc.com/teensy/pins.html
+	DDRD = 0x00;
+	DDRB = 0x00;
+	PORTB = 0xFF;
+	PORTD = 0xFF;
+
+	// Initialize the USB, and then wait for the host to set configuration.
+	// If the Teensy is powered without a PC connected to the USB port,
+	// this will wait forever.
+	usb_init();
+	while (!usb_configured()) /* wait */ ;
+
+	// Wait an extra second for the PC's operating system to load drivers
+	// and do whatever it does to actually be ready for input
+	_delay_ms(1000);
+
+	// Configure timer 0 to generate a timer overflow interrupt every
+	// 256*1024 clock cycles, or approx 61 Hz when using 16 MHz clock
+	// This demonstrates how to use interrupts to implement a simple
+	// inactivity timeout.
+	TCCR0A = 0x00;
+	TCCR0B = 0x05;
+	TIMSK0 = (1<<TOIE0);
+
+	print("Begin keyboard example program\n");
+	print("All Port B or Port D pins are inputs with pullup resistors.\n");
+	print("Any connection to ground on Port B or D pins will result in\n");
+	print("keystrokes sent to the PC (and debug messages here).\n");
+	while (1) {
+		// read all port B and port D pins
+		b = PINB;
+		d = PIND;
+		// check if any pins are low, but were high previously
+		mask = 1;
+		reset_idle = 0;
+		for (i=0; i<8; i++) {
+			if (((b & mask) == 0) && (b_prev & mask) != 0) {
+				usb_keyboard_press(KEY_B, KEY_SHIFT);
+				usb_keyboard_press(number_keys[i], 0);
+				print("Port B, bit ");
+				phex(i);
+				print("\n");
+				reset_idle = 1;
+			}
+			if (((d & mask) == 0) && (d_prev & mask) != 0) {
+				usb_keyboard_press(KEY_D, KEY_SHIFT);
+				usb_keyboard_press(number_keys[i], 0);
+				print("Port D, bit ");
+				phex(i);
+				print("\n");
+				reset_idle = 1;
+			}
+			mask = mask << 1;
+		}
+		// if any keypresses were detected, reset the idle counter
+		if (reset_idle) {
+			// variables shared with interrupt routines must be
+			// accessed carefully so the interrupt routine doesn't
+			// try to use the variable in the middle of our access
+			cli();
+			idle_count = 0;
+			sei();
+		}
+		// now the current pins will be the previous, and
+		// wait a short delay so we're not highly sensitive
+		// to mechanical "bounce".
+		b_prev = b;
+		d_prev = d;
+		_delay_ms(2);
+	}
+}
+
+// This interrupt routine is run approx 61 times per second.
+// A very simple inactivity timeout is implemented, where we
+// will send a space character and print a message to the
+// hid_listen debug message window.
+ISR(TIMER0_OVF_vect)
+{
+	idle_count++;
+	if (idle_count > 61 * 8) {
+		idle_count = 0;
+		print("Timer Event :)\n");
+		usb_keyboard_press(KEY_SPACE, 0);
+	}
+}
+
+