From: Russ Handorf <rhandorf@handorf.org>
Date: Sun, 14 Feb 2016 00:22:13 +0000 (-0500)
Subject: initial commit
X-Git-Url: https://handorf.org/code/?a=commitdiff_plain;h=HEAD;p=usb-nixie.git

initial commit
---

8dd6b17e344a0be33247035dcb05da4f42cb7483
diff --git a/.dep/nixie.o.d b/.dep/nixie.o.d
new file mode 100644
index 0000000..3879d73
--- /dev/null
+++ b/.dep/nixie.o.d
@@ -0,0 +1,3 @@
+nixie.o: nixie.c usb_serial.h
+
+usb_serial.h:
diff --git a/.dep/usb_serial.o.d b/.dep/usb_serial.o.d
new file mode 100644
index 0000000..d288ca5
--- /dev/null
+++ b/.dep/usb_serial.o.d
@@ -0,0 +1,3 @@
+usb_serial.o: usb_serial.c usb_serial.h
+
+usb_serial.h:
diff --git a/README b/README
new file mode 100644
index 0000000..68275b9
--- /dev/null
+++ b/README
@@ -0,0 +1,29 @@
+###############################################################################
+# The MIT License (MIT)
+# Copyright (c) Russell Handorf
+#
+# 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.
+#
+###############################################################################
+
+I made a 10 digit nixie display a long time ago, and at one point in time, had asterisk pushing caller ID to it.
+
+In this is the code to drive the display as a USB serial device using a Teensy.
+
+nixie-test.pl : This has some crude instructions for displaying the digits and making things pretty.
diff --git a/nixie-test.pl b/nixie-test.pl
new file mode 100755
index 0000000..98157f0
--- /dev/null
+++ b/nixie-test.pl
@@ -0,0 +1,318 @@
+#!/usr/bin/perl
+
+use strict;
+use Time::HiRes qw(usleep nanosleep);
+use NetServer::Generic;
+
+my $tty = "/dev/ttyACM0";
+
+my $digits = "1234567890";
+#$digits=reverse($digits);
+
+l_scroll($tty,$digits);
+sleep(1);
+r_scroll($tty,$digits);
+sleep(1);
+casino_all($tty,$digits);
+sleep(1);
+casino_one_r($tty,$digits);
+sleep(3);
+`/bin/echo '            ' > $tty`;
+print "FINISHED!\n";
+
+#  print "input: $tmp ".length($tmp)."\n";
+#  if (length($tmp)==10) {
+#    if (int(rand(10))>=6) {
+#      casino_one_r($tty,$tmp);
+#    } else {
+#      casino_all($tty,$tmp);
+#    }
+#  } else {
+#   if (int(rand(10))>=6) {
+#      l_scroll($tty,$tmp);
+#    } else {
+#      r_scroll($tty,$tmp);
+#    }
+#  }
+#  sleep(5);
+#  `/bin/echo '          ' > $tty`;
+#  return; 
+#};
+#}
+
+sub l_scroll { 
+  my $tty = shift;
+  my $digits = shift;
+  my $length=length($digits);
+  my @chars=split('',$digits);
+  #if ($length==10) {
+  #  `/bin/echo $digits > $tty`;
+  #  print "$digits\n";
+  #}
+  #if ($length!=10) {
+    my $display="          ";
+    `/bin/echo '$display' > $tty`;
+    my $i;
+    my $displaylen=10+$length;
+    while($i<=$displaylen) {
+      $display=$display.$chars[$i];
+      if ($length<=$i) {
+        $display=$display." ";
+      }
+      $i++;
+      $display=substr($display,1);
+      usleep(400000);
+      `/bin/echo '$display' > $tty`;
+      print "$display\n";
+    }
+  #}
+}
+
+sub r_scroll { 
+  my $tty = shift;
+  my $digits = shift;
+  my $length=length($digits);
+  my @chars=split('',$digits);
+  #if ($length==10) {
+  #  `/bin/echo $digits > $tty`;
+  #  print "$digits\n";
+  #}
+  #if ($length!=10) {
+    my $display="          ";
+    `/bin/echo '$display' > $tty`;
+    my $displaylen=10+$length;
+    my $i;
+    while($displaylen>0) {
+      $display=$chars[$i].$display;
+      if ($length<=$i) {
+        $display=" ".$display;
+      }
+      $i++;
+      $displaylen--;
+      $display=substr($display,0,-1);
+      usleep(400000);
+      `/bin/echo '$display' > $tty`;
+    }
+    usleep(400000);
+    `/bin/echo '$display' > $tty`;
+  #}
+}
+
+sub casino_all {
+  my $tty = shift;
+  my $digits = shift;
+  $digits= reverse($digits);
+  my $length=length($digits);
+  print "Starting Casino Random\n";
+  if ($length==10) {
+    my $i;
+    while ($i<50) {
+      my $r_digit=int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10));
+      `/bin/echo $r_digit > $tty`;
+      print "$r_digit\n";
+      usleep(50000);
+      $i++;
+    }
+    `/bin/echo $digits > $tty`;
+  }
+}
+
+sub casino_one_l {
+  my $tty = shift;
+  my $digits = shift;
+  my $length=length($digits);
+  my @chars=split('',$digits);
+  print "Starting Casino Digit Random\n";
+  if ($length==10) {
+    my $i;
+    while ($i<10) {
+      my $r_digit=int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10));
+      `/bin/echo $r_digit > $tty`;
+      usleep(50000);
+      $i++;
+    }
+    $digits=$chars[0].int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10));
+    `/bin/echo $digits > $tty`;
+    $i=0;
+    while ($i<10) {
+      my $r_digit=$chars[0].int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10));
+      `/bin/echo $r_digit > $tty`;
+      usleep(50000);
+      $i++;
+    }
+    $digits=$chars[0].$chars[1].int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10));
+    `/bin/echo $digits > $tty`;
+    $i=0;
+    while ($i<10) {
+      my $r_digit=$chars[0].$chars[1].int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10));
+      `/bin/echo $r_digit > $tty`;
+      usleep(50000);
+      $i++;
+    }
+    $digits=$chars[0].$chars[1].$chars[2].int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10));
+    `/bin/echo $digits > $tty`;
+    $i=0;
+    while ($i<10) {
+      my $r_digit=$chars[0].$chars[1].$chars[2].int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10));
+      `/bin/echo $r_digit > $tty`;
+      usleep(50000);
+      $i++;
+    }
+    $digits=$chars[0].$chars[1].$chars[2].$chars[3].int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10));
+    `/bin/echo $digits > $tty`;
+    $i=0;
+    while ($i<10) {
+      my $r_digit=$chars[0].$chars[1].$chars[2].$chars[3].int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10));
+      `/bin/echo $r_digit > $tty`;
+      usleep(50000);
+      $i++;
+    }
+    $digits=$chars[0].$chars[1].$chars[2].$chars[3].$chars[4].int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10));
+    `/bin/echo $digits > $tty`;
+    $i=0;
+    while ($i<10) {
+      my $r_digit=$chars[0].$chars[1].$chars[2].$chars[3].$chars[4].int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10));
+      `/bin/echo $r_digit > $tty`;
+      usleep(50000);
+      $i++;
+    }
+    $digits=$chars[0].$chars[1].$chars[2].$chars[3].$chars[4].$chars[5].int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10));
+    `/bin/echo $digits > $tty`;
+    $i=0;
+    while ($i<10) {
+      my $r_digit=$chars[0].$chars[1].$chars[2].$chars[3].$chars[4].$chars[5].int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10));
+      `/bin/echo $r_digit > $tty`;
+      usleep(50000);
+      $i++;
+    }
+    $digits=$chars[0].$chars[1].$chars[2].$chars[3].$chars[4].$chars[5].$chars[6].int(rand(10)).int(rand(10)).int(rand(10));
+    `/bin/echo $digits > $tty`;
+    $i=0;
+    while ($i<10) {
+      my $r_digit=$chars[0].$chars[1].$chars[2].$chars[3].$chars[4].$chars[5].$chars[6].int(rand(10)).int(rand(10)).int(rand(10));
+      `/bin/echo $r_digit > $tty`;
+      usleep(50000);
+      $i++;
+    }
+    $digits=$chars[0].$chars[1].$chars[2].$chars[3].$chars[4].$chars[5].$chars[6].$chars[7].int(rand(10)).int(rand(10));
+    `/bin/echo $digits > $tty`;
+    $i=0;
+    while ($i<10) {
+      my $r_digit=$chars[0].$chars[1].$chars[2].$chars[3].$chars[4].$chars[5].$chars[6].$chars[7].int(rand(10)).int(rand(10));
+      `/bin/echo $r_digit > $tty`;
+      usleep(50000);
+      $i++;
+    }
+    $digits=$chars[0].$chars[1].$chars[2].$chars[3].$chars[4].$chars[5].$chars[6].$chars[7].$chars[8].int(rand(10));
+    `/bin/echo $digits > $tty`;
+    $i=0;
+    while ($i<10) {
+      my $r_digit=$chars[0].$chars[1].$chars[2].$chars[3].$chars[4].$chars[5].$chars[6].$chars[7].$chars[8].int(rand(10));
+      `/bin/echo $r_digit > $tty`;
+      usleep(50000);
+      $i++;
+    }
+    $digits=$chars[0].$chars[1].$chars[2].$chars[3].$chars[4].$chars[5].$chars[6].$chars[7].$chars[8].$chars[9];
+    `/bin/echo $digits > $tty`;
+  }
+}
+
+sub casino_one_r {
+  my $tty = shift;
+  my $digits = shift;
+  my $length=length($digits);
+  my @chars=split('',$digits);
+  print "Starting Casino Digit Random\n";
+  if ($length==10) {
+    my $i;
+    while ($i<10) {
+      my $r_digit=int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10));
+      `/bin/echo $r_digit > $tty`;
+      usleep(50000);
+      $i++;
+    }
+    $digits=int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).$chars[0];
+    `/bin/echo $digits > $tty`;
+    $i=0;
+    while ($i<10) {
+      my $r_digit=int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).$chars[0];
+      `/bin/echo $r_digit > $tty`;
+      usleep(50000);
+      $i++;
+    }
+    $digits=int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).$chars[1].$chars[0];
+    `/bin/echo $digits > $tty`;
+    $i=0;
+    while ($i<10) {
+      my $r_digit=int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).$chars[1].$chars[0];
+      `/bin/echo $r_digit > $tty`;
+      usleep(50000);
+      $i++;
+    }
+    $digits=int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).$chars[2].$chars[1].$chars[0];
+    `/bin/echo $digits > $tty`;
+    $i=0;
+    while ($i<10) {
+      my $r_digit=int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).$chars[2].$chars[1].$chars[0];
+      `/bin/echo $r_digit > $tty`;
+      usleep(50000);
+      $i++;
+    }
+    $digits=int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).$chars[3].$chars[2].$chars[1].$chars[0];
+    `/bin/echo $digits > $tty`;
+    $i=0;
+    while ($i<10) {
+      my $r_digit=int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).$chars[3].$chars[2].$chars[1].$chars[0];
+      `/bin/echo $r_digit > $tty`;
+      usleep(50000);
+      $i++;
+    }
+    $digits=int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).$chars[4].$chars[3].$chars[2].$chars[1].$chars[0];
+    `/bin/echo $digits > $tty`;
+    $i=0;
+    while ($i<10) {
+      my $r_digit=int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).$chars[4].$chars[3].$chars[2].$chars[1].$chars[0];
+      `/bin/echo $r_digit > $tty`;
+      usleep(50000);
+      $i++;
+    }
+    $digits=int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).$chars[5].$chars[4].$chars[3].$chars[2].$chars[1].$chars[0];
+    `/bin/echo $digits > $tty`;
+    $i=0;
+    while ($i<10) {
+      my $r_digit=int(rand(10)).int(rand(10)).int(rand(10)).int(rand(10)).$chars[5].$chars[4].$chars[3].$chars[2].$chars[1].$chars[0];
+      `/bin/echo $r_digit > $tty`;
+      usleep(50000);
+      $i++;
+    }
+    $digits=int(rand(10)).int(rand(10)).int(rand(10)).$chars[6].$chars[5].$chars[4].$chars[3].$chars[2].$chars[1].$chars[0];
+    `/bin/echo $digits > $tty`;
+    $i=0;
+    while ($i<10) {
+      my $r_digit=int(rand(10)).int(rand(10)).int(rand(10)).$chars[6].$chars[5].$chars[4].$chars[3].$chars[2].$chars[1].$chars[0];
+      `/bin/echo $r_digit > $tty`;
+      usleep(50000);
+      $i++;
+    }
+    $digits=int(rand(10)).int(rand(10)).$chars[7].$chars[6].$chars[5].$chars[4].$chars[3].$chars[2].$chars[1].$chars[0];
+    `/bin/echo $digits > $tty`;
+    $i=0;
+    while ($i<10) {
+      my $r_digit=int(rand(10)).int(rand(10)).$chars[7].$chars[6].$chars[5].$chars[4].$chars[3].$chars[2].$chars[1].$chars[0];
+      `/bin/echo $r_digit > $tty`;
+      usleep(50000);
+      $i++;
+    }
+    $digits=int(rand(10)).$chars[8].$chars[7].$chars[6].$chars[5].$chars[4].$chars[3].$chars[2].$chars[1].$chars[0];
+    `/bin/echo $digits > $tty`;
+    $i=0;
+    while ($i<10) {
+      my $r_digit=int(rand(10)).$chars[8].$chars[7].$chars[6].$chars[5].$chars[4].$chars[3].$chars[2].$chars[1].$chars[0];
+      `/bin/echo $r_digit > $tty`;
+      usleep(50000);
+      $i++;
+    }
+    $digits=$chars[9].$chars[8].$chars[7].$chars[6].$chars[5].$chars[4].$chars[3].$chars[2].$chars[1].$chars[0];
+    `/bin/echo $digits > $tty`;
+  }
+}
diff --git a/nixie.c b/nixie.c
new file mode 100644
index 0000000..1f0a1e6
--- /dev/null
+++ b/nixie.c
@@ -0,0 +1,267 @@
+/* Teensy Serial to OGI Lumen Nixie Driver board  rev 0.1
+ * 
+ * Based on (read as "a quick hack of"):
+ * Simple example for Teensy USB Development Board
+ * http://www.pjrc.com/teensy/
+ * 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.
+ */
+
+/* 
+ * Nixie Driver Pin	Teensy Pin
+ * -------      	---------
+ * 2  GND		GND
+ * 5  Vcc		+5v
+ * 1  SER		D4
+ * 3  SCK		D5
+ * 4  RCK		D6
+ * 6  NC		-
+ *
+ * For 3d-ish effects:
+ * Nixie digit order, front to back:  3894057621
+ */
+
+#include <avr/io.h>
+#include <avr/pgmspace.h>
+#include <stdint.h>
+#include <util/delay.h>
+#include "usb_serial.h"
+
+#define CPU_PRESCALE(n) (CLKPR = 0x80, CLKPR = (n))
+#define NIXIE_SER	(1 << 4)
+#define NIXIE_SCK	(1 << 5)
+#define NIXIE_RCK	(1 << 6)
+
+void send_str(const char *s);
+uint8_t recv_str(char *buf, uint8_t size);
+void parse_and_execute_command(const char *buf, uint8_t num);
+
+void nixie_init(void)
+{
+	PORTD &= ~(NIXIE_SER);
+	PORTD &= ~(NIXIE_SCK);
+	PORTD &= ~(NIXIE_RCK);
+	DDRD |= (NIXIE_SER | NIXIE_SCK | NIXIE_RCK);
+}
+
+void nixie_send_digit(uint8_t digit)
+{
+	for (int i=0; i < 4; i++) {
+		PORTD &= ~(NIXIE_SCK);	
+		if ((digit & 0x8) != 0) {
+			PORTD |= NIXIE_SER;
+		} else {
+			PORTD &= ~(NIXIE_SER);	
+		}
+		_delay_us(10);
+		PORTD |= NIXIE_SCK;
+		_delay_us(10);
+		digit <<= 1;
+	}
+	PORTD &= ~(NIXIE_SCK);
+	PORTD |= NIXIE_SER;
+	_delay_us(10);
+}
+
+void nixie_show(void)
+{
+	PORTD |= NIXIE_RCK;
+	_delay_us(10);
+	PORTD &= ~(NIXIE_RCK);
+	_delay_us(10);
+}
+
+int main(void)
+{
+	char buf[32];
+	uint8_t n;
+
+	// set for 16 MHz clock, and turn on the LED
+	CPU_PRESCALE(0);
+
+	// 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 */ ;
+	_delay_ms(1000);
+	nixie_init();
+	_delay_ms(2);
+	nixie_send_digit(8);
+	nixie_send_digit(7);
+	nixie_send_digit(6);
+	nixie_send_digit(5);
+	nixie_send_digit(4);
+	nixie_send_digit(3);
+	nixie_send_digit(2);
+	nixie_send_digit(1);
+	nixie_show();
+
+	while (1) {
+		// wait for the user to run their terminal emulator program
+		// which sets DTR to indicate it is ready to receive.
+		while (!(usb_serial_get_control() & USB_SERIAL_DTR)) /* wait */ ;
+
+		// discard anything that was received prior.  Sometimes the
+		// operating system or other software will send a modem
+		// "AT command", which can still be buffered.
+		usb_serial_flush_input();
+
+		// print a nice welcome message
+		send_str(PSTR("\r\nTeensy USB Serial Example, "
+			"Simple Pin Control Shell\r\n\r\n"
+			"Example Commands\r\n"
+			"  B0?   Read Port B, pin 0\r\n"
+			"  C2=0  Write Port C, pin 1 LOW\r\n"
+			"  D6=1  Write Port D, pin 6 HIGH  (D6 is LED pin)\r\n\r\n"));
+
+		// and then listen for commands and process them
+		while (1) {
+			send_str(PSTR("> "));
+			n = recv_str(buf, sizeof(buf));
+			if (n == 255) break;
+			send_str(PSTR("\r\n"));
+			// parse_and_execute_command(buf, n);
+		}
+	}
+}
+
+// Send a string to the USB serial port.  The string must be in
+// flash memory, using PSTR
+//
+void send_str(const char *s)
+{
+	char c;
+	while (1) {
+		c = pgm_read_byte(s++);
+		if (!c) break;
+		usb_serial_putchar(c);
+	}
+}
+
+// Receive a string from the USB serial port.  The string is stored
+// in the buffer and this function will not exceed the buffer size.
+// A carriage return or newline completes the string, and is not
+// stored into the buffer.
+// The return value is the number of characters received, or 255 if
+// the virtual serial connection was closed while waiting.
+//
+uint8_t recv_str(char *buf, uint8_t size)
+{
+	int16_t r;
+	uint8_t count=0;
+
+	while (count < size) {
+		r = usb_serial_getchar();
+		if (r != -1) {
+			if (r == '\r' || r == '\n') {
+				nixie_show();	
+				return count;
+			}
+			if (r >= '0' && r <= '9') {
+				*buf++ = r;
+				usb_serial_putchar(r);
+				nixie_send_digit(r);
+				count++;
+			} else if (r == ' ') {
+				usb_serial_putchar(r);
+				nixie_send_digit(10);
+			}
+		} else {
+			if (!usb_configured() ||
+			  !(usb_serial_get_control() & USB_SERIAL_DTR)) {
+				// user no longer connected
+				return 255;
+			}
+			// just a normal timeout, keep waiting
+		}
+	}
+	return count;
+}
+
+// parse a user command and execute it, or print an error message
+//
+void parse_and_execute_command(const char *buf, uint8_t num)
+{
+	uint8_t port, pin, val;
+
+	if (num < 3) {
+		send_str(PSTR("unrecognized format, 3 chars min req'd\r\n"));
+		return;
+	}
+	// first character is the port letter
+	if (buf[0] >= 'A' && buf[0] <= 'F') {
+		port = buf[0] - 'A';
+	} else if (buf[0] >= 'a' && buf[0] <= 'f') {
+		port = buf[0] - 'a';
+	} else {
+		send_str(PSTR("Unknown port \""));
+		usb_serial_putchar(buf[0]);
+		send_str(PSTR("\", must be A - F\r\n"));
+		return;
+	}
+	// second character is the pin number
+	if (buf[1] >= '0' && buf[1] <= '7') {
+		pin = buf[1] - '0';
+	} else {
+		send_str(PSTR("Unknown pin \""));
+		usb_serial_putchar(buf[0]);
+		send_str(PSTR("\", must be 0 to 7\r\n"));
+		return;
+	}
+	// if the third character is a question mark, read the pin
+	if (buf[2] == '?') {
+		// make the pin an input
+		*(uint8_t *)(0x21 + port * 3) &= ~(1 << pin);
+		// read the pin
+		val = *(uint8_t *)(0x20 + port * 3) & (1 << pin);
+		usb_serial_putchar(val ? '1' : '0');
+		send_str(PSTR("\r\n"));
+		return;
+	}
+	// if the third character is an equals sign, write the pin
+	if (num >= 4 && buf[2] == '=') {
+		if (buf[3] == '0') {
+			// make the pin an output
+			*(uint8_t *)(0x21 + port * 3) |= (1 << pin);
+			// drive it low
+			*(uint8_t *)(0x22 + port * 3) &= ~(1 << pin);
+			return;
+		} else if (buf[3] == '1') {
+			// make the pin an output
+			*(uint8_t *)(0x21 + port * 3) |= (1 << pin);
+			// drive it high
+			*(uint8_t *)(0x22 + port * 3) |= (1 << pin);
+			return;
+		} else {
+			send_str(PSTR("Unknown value \""));
+			usb_serial_putchar(buf[3]);
+			send_str(PSTR("\", must be 0 or 1\r\n"));
+			return;
+		}
+	}
+	// otherwise, error message
+	send_str(PSTR("Unknown command \""));
+	usb_serial_putchar(buf[0]);
+	send_str(PSTR("\", must be ? or =\r\n"));
+}
+
+
diff --git a/usb_serial.c b/usb_serial.c
new file mode 100644
index 0000000..4a9f47e
--- /dev/null
+++ b/usb_serial.c
@@ -0,0 +1,927 @@
+/* USB Serial Example for Teensy USB Development Board
+ * http://www.pjrc.com/teensy/
+ * 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.
+ */
+
+// Version 1.0: Initial Release
+// Version 1.1: support Teensy++
+// Version 1.2: fixed usb_serial_available
+// Version 1.3: added transmit bandwidth test
+// Version 1.4: added usb_serial_write
+// Version 1.5: add support for Teensy 2.0
+
+#define USB_SERIAL_PRIVATE_INCLUDE
+#include "usb_serial.h"
+
+
+/**************************************************************************
+ *
+ *  Configurable Options
+ *
+ **************************************************************************/
+
+// You can change these to give your code its own name.  On Windows,
+// these are only used before an INF file (driver install) is loaded.
+#define STR_MANUFACTURER	L"Your Name"
+#define STR_PRODUCT		L"USB Serial"
+
+// All USB serial devices are supposed to have a serial number
+// (according to Microsoft).  On windows, a new COM port is created
+// for every unique serial/vendor/product number combination.  If
+// you program 2 identical boards with 2 different serial numbers
+// and they are assigned COM7 and COM8, each will always get the
+// same COM port number because Windows remembers serial numbers.
+//
+// On Mac OS-X, a device file is created automatically which
+// incorperates the serial number, eg, /dev/cu-usbmodem12341
+//
+// Linux by default ignores the serial number, and creates device
+// files named /dev/ttyACM0, /dev/ttyACM1... in the order connected.
+// Udev rules (in /etc/udev/rules.d) can define persistent device
+// names linked to this serial number, as well as permissions, owner
+// and group settings.
+#define STR_SERIAL_NUMBER	L"12345"
+
+// Mac OS-X and Linux automatically load the correct drivers.  On
+// Windows, even though the driver is supplied by Microsoft, an
+// INF file is needed to load the driver.  These numbers need to
+// match the INF file.
+#define VENDOR_ID		0x16C0
+#define PRODUCT_ID		0x047A
+
+// When you write data, it goes into a USB endpoint buffer, which
+// is transmitted to the PC when it becomes full, or after a timeout
+// with no more writes.  Even if you write in exactly packet-size
+// increments, this timeout is used to send a "zero length packet"
+// that tells the PC no more data is expected and it should pass
+// any buffered data to the application that may be waiting.  If
+// you want data sent immediately, call usb_serial_flush_output().
+#define TRANSMIT_FLUSH_TIMEOUT	5   /* in milliseconds */
+
+// If the PC is connected but not "listening", this is the length
+// of time before usb_serial_getchar() returns with an error.  This
+// is roughly equivilant to a real UART simply transmitting the
+// bits on a wire where nobody is listening, except you get an error
+// code which you can ignore for serial-like discard of data, or
+// use to know your data wasn't sent.
+#define TRANSMIT_TIMEOUT	25   /* in milliseconds */
+
+// USB devices are supposed to implment a halt feature, which is
+// rarely (if ever) used.  If you comment this line out, the halt
+// code will be removed, saving 116 bytes of space (gcc 4.3.0).
+// This is not strictly USB compliant, but works with all major
+// operating systems.
+#define SUPPORT_ENDPOINT_HALT
+
+
+
+/**************************************************************************
+ *
+ *  Endpoint Buffer Configuration
+ *
+ **************************************************************************/
+
+// These buffer sizes are best for most applications, but perhaps if you
+// want more buffering on some endpoint at the expense of others, this
+// is where you can make such changes.  The AT90USB162 has only 176 bytes
+// of DPRAM (USB buffers) and only endpoints 3 & 4 can double buffer.
+
+#define ENDPOINT0_SIZE		16
+#define CDC_ACM_ENDPOINT	2
+#define CDC_RX_ENDPOINT		3
+#define CDC_TX_ENDPOINT		4
+#if defined(__AVR_AT90USB162__)
+#define CDC_ACM_SIZE		16
+#define CDC_ACM_BUFFER		EP_SINGLE_BUFFER
+#define CDC_RX_SIZE		32
+#define CDC_RX_BUFFER 		EP_DOUBLE_BUFFER
+#define CDC_TX_SIZE		32
+#define CDC_TX_BUFFER		EP_DOUBLE_BUFFER
+#else
+#define CDC_ACM_SIZE		16
+#define CDC_ACM_BUFFER		EP_SINGLE_BUFFER
+#define CDC_RX_SIZE		64
+#define CDC_RX_BUFFER 		EP_DOUBLE_BUFFER
+#define CDC_TX_SIZE		64
+#define CDC_TX_BUFFER		EP_DOUBLE_BUFFER
+#endif
+
+static const uint8_t PROGMEM endpoint_config_table[] = {
+	0,
+	1, EP_TYPE_INTERRUPT_IN,  EP_SIZE(CDC_ACM_SIZE) | CDC_ACM_BUFFER,
+	1, EP_TYPE_BULK_OUT,      EP_SIZE(CDC_RX_SIZE) | CDC_RX_BUFFER,
+	1, EP_TYPE_BULK_IN,       EP_SIZE(CDC_TX_SIZE) | CDC_TX_BUFFER
+};
+
+
+/**************************************************************************
+ *
+ *  Descriptor Data
+ *
+ **************************************************************************/
+
+// Descriptors are the data that your computer reads when it auto-detects
+// this USB device (called "enumeration" in USB lingo).  The most commonly
+// changed items are editable at the top of this file.  Changing things
+// in here should only be done by those who've read chapter 9 of the USB
+// spec and relevant portions of any USB class specifications!
+
+static uint8_t PROGMEM device_descriptor[] = {
+	18,					// bLength
+	1,					// bDescriptorType
+	0x00, 0x02,				// bcdUSB
+	2,					// bDeviceClass
+	0,					// bDeviceSubClass
+	0,					// bDeviceProtocol
+	ENDPOINT0_SIZE,				// bMaxPacketSize0
+	LSB(VENDOR_ID), MSB(VENDOR_ID),		// idVendor
+	LSB(PRODUCT_ID), MSB(PRODUCT_ID),	// idProduct
+	0x00, 0x01,				// bcdDevice
+	1,					// iManufacturer
+	2,					// iProduct
+	3,					// iSerialNumber
+	1					// bNumConfigurations
+};
+
+#define CONFIG1_DESC_SIZE (9+9+5+5+4+5+7+9+7+7)
+static uint8_t PROGMEM config1_descriptor[CONFIG1_DESC_SIZE] = {
+	// configuration descriptor, USB spec 9.6.3, page 264-266, Table 9-10
+	9, 					// bLength;
+	2,					// bDescriptorType;
+	LSB(CONFIG1_DESC_SIZE),			// wTotalLength
+	MSB(CONFIG1_DESC_SIZE),
+	2,					// bNumInterfaces
+	1,					// bConfigurationValue
+	0,					// iConfiguration
+	0xC0,					// bmAttributes
+	50,					// bMaxPower
+	// interface descriptor, USB spec 9.6.5, page 267-269, Table 9-12
+	9,					// bLength
+	4,					// bDescriptorType
+	0,					// bInterfaceNumber
+	0,					// bAlternateSetting
+	1,					// bNumEndpoints
+	0x02,					// bInterfaceClass
+	0x02,					// bInterfaceSubClass
+	0x01,					// bInterfaceProtocol
+	0,					// iInterface
+	// CDC Header Functional Descriptor, CDC Spec 5.2.3.1, Table 26
+	5,					// bFunctionLength
+	0x24,					// bDescriptorType
+	0x00,					// bDescriptorSubtype
+	0x10, 0x01,				// bcdCDC
+	// Call Management Functional Descriptor, CDC Spec 5.2.3.2, Table 27
+	5,					// bFunctionLength
+	0x24,					// bDescriptorType
+	0x01,					// bDescriptorSubtype
+	0x01,					// bmCapabilities
+	1,					// bDataInterface
+	// Abstract Control Management Functional Descriptor, CDC Spec 5.2.3.3, Table 28
+	4,					// bFunctionLength
+	0x24,					// bDescriptorType
+	0x02,					// bDescriptorSubtype
+	0x06,					// bmCapabilities
+	// Union Functional Descriptor, CDC Spec 5.2.3.8, Table 33
+	5,					// bFunctionLength
+	0x24,					// bDescriptorType
+	0x06,					// bDescriptorSubtype
+	0,					// bMasterInterface
+	1,					// bSlaveInterface0
+	// endpoint descriptor, USB spec 9.6.6, page 269-271, Table 9-13
+	7,					// bLength
+	5,					// bDescriptorType
+	CDC_ACM_ENDPOINT | 0x80,		// bEndpointAddress
+	0x03,					// bmAttributes (0x03=intr)
+	CDC_ACM_SIZE, 0,			// wMaxPacketSize
+	64,					// bInterval
+	// interface descriptor, USB spec 9.6.5, page 267-269, Table 9-12
+	9,					// bLength
+	4,					// bDescriptorType
+	1,					// bInterfaceNumber
+	0,					// bAlternateSetting
+	2,					// bNumEndpoints
+	0x0A,					// bInterfaceClass
+	0x00,					// bInterfaceSubClass
+	0x00,					// bInterfaceProtocol
+	0,					// iInterface
+	// endpoint descriptor, USB spec 9.6.6, page 269-271, Table 9-13
+	7,					// bLength
+	5,					// bDescriptorType
+	CDC_RX_ENDPOINT,			// bEndpointAddress
+	0x02,					// bmAttributes (0x02=bulk)
+	CDC_RX_SIZE, 0,				// wMaxPacketSize
+	0,					// bInterval
+	// endpoint descriptor, USB spec 9.6.6, page 269-271, Table 9-13
+	7,					// bLength
+	5,					// bDescriptorType
+	CDC_TX_ENDPOINT | 0x80,			// bEndpointAddress
+	0x02,					// bmAttributes (0x02=bulk)
+	CDC_TX_SIZE, 0,				// wMaxPacketSize
+	0					// bInterval
+};
+
+// If you're desperate for a little extra code memory, these strings
+// can be completely removed if iManufacturer, iProduct, iSerialNumber
+// in the device desciptor are changed to zeros.
+struct usb_string_descriptor_struct {
+	uint8_t bLength;
+	uint8_t bDescriptorType;
+	int16_t wString[];
+};
+static struct usb_string_descriptor_struct PROGMEM string0 = {
+	4,
+	3,
+	{0x0409}
+};
+static struct usb_string_descriptor_struct PROGMEM string1 = {
+	sizeof(STR_MANUFACTURER),
+	3,
+	STR_MANUFACTURER
+};
+static struct usb_string_descriptor_struct PROGMEM string2 = {
+	sizeof(STR_PRODUCT),
+	3,
+	STR_PRODUCT
+};
+static struct usb_string_descriptor_struct PROGMEM string3 = {
+	sizeof(STR_SERIAL_NUMBER),
+	3,
+	STR_SERIAL_NUMBER
+};
+
+// This table defines which descriptor data is sent for each specific
+// request from the host (in wValue and wIndex).
+static struct descriptor_list_struct {
+	uint16_t	wValue;
+	uint16_t	wIndex;
+	const uint8_t	*addr;
+	uint8_t		length;
+} PROGMEM descriptor_list[] = {
+	{0x0100, 0x0000, device_descriptor, sizeof(device_descriptor)},
+	{0x0200, 0x0000, config1_descriptor, sizeof(config1_descriptor)},
+	{0x0300, 0x0000, (const uint8_t *)&string0, 4},
+	{0x0301, 0x0409, (const uint8_t *)&string1, sizeof(STR_MANUFACTURER)},
+	{0x0302, 0x0409, (const uint8_t *)&string2, sizeof(STR_PRODUCT)},
+	{0x0303, 0x0409, (const uint8_t *)&string3, sizeof(STR_SERIAL_NUMBER)}
+};
+#define NUM_DESC_LIST (sizeof(descriptor_list)/sizeof(struct descriptor_list_struct))
+
+
+/**************************************************************************
+ *
+ *  Variables - these are the only non-stack RAM usage
+ *
+ **************************************************************************/
+
+// zero when we are not configured, non-zero when enumerated
+static volatile uint8_t usb_configuration=0;
+
+// the time remaining before we transmit any partially full
+// packet, or send a zero length packet.
+static volatile uint8_t transmit_flush_timer=0;
+static uint8_t transmit_previous_timeout=0;
+
+// serial port settings (baud rate, control signals, etc) set
+// by the PC.  These are ignored, but kept in RAM.
+static uint8_t cdc_line_coding[7]={0x00, 0xE1, 0x00, 0x00, 0x00, 0x00, 0x08};
+static uint8_t cdc_line_rtsdtr=0;
+
+
+/**************************************************************************
+ *
+ *  Public Functions - these are the API intended for the user
+ *
+ **************************************************************************/
+
+// initialize USB serial
+void usb_init(void)
+{
+	HW_CONFIG();
+        USB_FREEZE();				// enable USB
+        PLL_CONFIG();				// config PLL, 16 MHz xtal
+        while (!(PLLCSR & (1<<PLOCK))) ;	// wait for PLL lock
+        USB_CONFIG();				// start USB clock
+        UDCON = 0;				// enable attach resistor
+	usb_configuration = 0;
+	cdc_line_rtsdtr = 0;
+        UDIEN = (1<<EORSTE)|(1<<SOFE);
+	sei();
+}
+
+// return 0 if the USB is not configured, or the configuration
+// number selected by the HOST
+uint8_t usb_configured(void)
+{
+	return usb_configuration;
+}
+
+// get the next character, or -1 if nothing received
+int16_t usb_serial_getchar(void)
+{
+	uint8_t c, intr_state;
+
+	// interrupts are disabled so these functions can be
+	// used from the main program or interrupt context,
+	// even both in the same program!
+	intr_state = SREG;
+	cli();
+	if (!usb_configuration) {
+		SREG = intr_state;
+		return -1;
+	}
+	UENUM = CDC_RX_ENDPOINT;
+	if (!(UEINTX & (1<<RWAL))) {
+		// no data in buffer
+		SREG = intr_state;
+		return -1;
+	}
+	// take one byte out of the buffer
+	c = UEDATX;
+	// if buffer completely used, release it
+	if (!(UEINTX & (1<<RWAL))) UEINTX = 0x6B;
+	SREG = intr_state;
+	return c;
+}
+
+// number of bytes available in the receive buffer
+uint8_t usb_serial_available(void)
+{
+	uint8_t n=0, intr_state;
+
+	intr_state = SREG;
+	cli();
+	if (usb_configuration) {
+		UENUM = CDC_RX_ENDPOINT;
+		n = UEBCLX;
+	}
+	SREG = intr_state;
+	return n;
+}
+
+// discard any buffered input
+void usb_serial_flush_input(void)
+{
+	uint8_t intr_state;
+
+	if (usb_configuration) {
+		intr_state = SREG;
+		cli();
+		UENUM = CDC_RX_ENDPOINT;
+		while ((UEINTX & (1<<RWAL))) {
+			UEINTX = 0x6B; 
+		}
+		SREG = intr_state;
+	}
+}
+
+// transmit a character.  0 returned on success, -1 on error
+int8_t usb_serial_putchar(uint8_t c)
+{
+	uint8_t timeout, intr_state;
+
+	// if we're not online (enumerated and configured), error
+	if (!usb_configuration) return -1;
+	// interrupts are disabled so these functions can be
+	// used from the main program or interrupt context,
+	// even both in the same program!
+	intr_state = SREG;
+	cli();
+	UENUM = CDC_TX_ENDPOINT;
+	// if we gave up due to timeout before, don't wait again
+	if (transmit_previous_timeout) {
+		if (!(UEINTX & (1<<RWAL))) {
+			SREG = intr_state;
+			return -1;
+		}
+		transmit_previous_timeout = 0;
+	}
+	// wait for the FIFO to be ready to accept data
+	timeout = UDFNUML + TRANSMIT_TIMEOUT;
+	while (1) {
+		// are we ready to transmit?
+		if (UEINTX & (1<<RWAL)) break;
+		SREG = intr_state;
+		// have we waited too long?  This happens if the user
+		// is not running an application that is listening
+		if (UDFNUML == timeout) {
+			transmit_previous_timeout = 1;
+			return -1;
+		}
+		// has the USB gone offline?
+		if (!usb_configuration) return -1;
+		// get ready to try checking again
+		intr_state = SREG;
+		cli();
+		UENUM = CDC_TX_ENDPOINT;
+	}
+	// actually write the byte into the FIFO
+	UEDATX = c;
+	// if this completed a packet, transmit it now!
+	if (!(UEINTX & (1<<RWAL))) UEINTX = 0x3A;
+	transmit_flush_timer = TRANSMIT_FLUSH_TIMEOUT;
+	SREG = intr_state;
+	return 0;
+}
+
+
+// transmit a character, but do not wait if the buffer is full,
+//   0 returned on success, -1 on buffer full or error 
+int8_t usb_serial_putchar_nowait(uint8_t c)
+{
+	uint8_t intr_state;
+
+	if (!usb_configuration) return -1;
+	intr_state = SREG;
+	cli();
+	UENUM = CDC_TX_ENDPOINT;
+	if (!(UEINTX & (1<<RWAL))) {
+		// buffer is full
+		SREG = intr_state;
+		return -1;
+	}
+	// actually write the byte into the FIFO
+	UEDATX = c;
+		// if this completed a packet, transmit it now!
+	if (!(UEINTX & (1<<RWAL))) UEINTX = 0x3A;
+	transmit_flush_timer = TRANSMIT_FLUSH_TIMEOUT;
+	SREG = intr_state;
+	return 0;
+}
+
+// transmit a buffer.
+//  0 returned on success, -1 on error
+// This function is optimized for speed!  Each call takes approx 6.1 us overhead
+// plus 0.25 us per byte.  12 Mbit/sec USB has 8.67 us per-packet overhead and
+// takes 0.67 us per byte.  If called with 64 byte packet-size blocks, this function
+// can transmit at full USB speed using 43% CPU time.  The maximum theoretical speed
+// is 19 packets per USB frame, or 1216 kbytes/sec.  However, bulk endpoints have the
+// lowest priority, so any other USB devices will likely reduce the speed.  Speed
+// can also be limited by how quickly the PC-based software reads data, as the host
+// controller in the PC will not allocate bandwitdh without a pending read request.
+// (thanks to Victor Suarez for testing and feedback and initial code)
+
+int8_t usb_serial_write(const uint8_t *buffer, uint16_t size)
+{
+	uint8_t timeout, intr_state, write_size;
+
+	// if we're not online (enumerated and configured), error
+	if (!usb_configuration) return -1;
+	// interrupts are disabled so these functions can be
+	// used from the main program or interrupt context,
+	// even both in the same program!
+	intr_state = SREG;
+	cli();
+	UENUM = CDC_TX_ENDPOINT;
+	// if we gave up due to timeout before, don't wait again
+	if (transmit_previous_timeout) {
+		if (!(UEINTX & (1<<RWAL))) {
+			SREG = intr_state;
+			return -1;
+		}
+		transmit_previous_timeout = 0;
+	}
+	// each iteration of this loop transmits a packet
+	while (size) {
+		// wait for the FIFO to be ready to accept data
+		timeout = UDFNUML + TRANSMIT_TIMEOUT;
+		while (1) {
+			// are we ready to transmit?
+			if (UEINTX & (1<<RWAL)) break;
+			SREG = intr_state;
+			// have we waited too long?  This happens if the user
+			// is not running an application that is listening
+			if (UDFNUML == timeout) {
+				transmit_previous_timeout = 1;
+				return -1;
+			}
+			// has the USB gone offline?
+			if (!usb_configuration) return -1;
+			// get ready to try checking again
+			intr_state = SREG;
+			cli();
+			UENUM = CDC_TX_ENDPOINT;
+		}
+
+		// compute how many bytes will fit into the next packet
+		write_size = CDC_TX_SIZE - UEBCLX;
+		if (write_size > size) write_size = size;
+		size -= write_size;
+
+		// write the packet
+		switch (write_size) {
+			#if (CDC_TX_SIZE == 64)
+			case 64: UEDATX = *buffer++;
+			case 63: UEDATX = *buffer++;
+			case 62: UEDATX = *buffer++;
+			case 61: UEDATX = *buffer++;
+			case 60: UEDATX = *buffer++;
+			case 59: UEDATX = *buffer++;
+			case 58: UEDATX = *buffer++;
+			case 57: UEDATX = *buffer++;
+			case 56: UEDATX = *buffer++;
+			case 55: UEDATX = *buffer++;
+			case 54: UEDATX = *buffer++;
+			case 53: UEDATX = *buffer++;
+			case 52: UEDATX = *buffer++;
+			case 51: UEDATX = *buffer++;
+			case 50: UEDATX = *buffer++;
+			case 49: UEDATX = *buffer++;
+			case 48: UEDATX = *buffer++;
+			case 47: UEDATX = *buffer++;
+			case 46: UEDATX = *buffer++;
+			case 45: UEDATX = *buffer++;
+			case 44: UEDATX = *buffer++;
+			case 43: UEDATX = *buffer++;
+			case 42: UEDATX = *buffer++;
+			case 41: UEDATX = *buffer++;
+			case 40: UEDATX = *buffer++;
+			case 39: UEDATX = *buffer++;
+			case 38: UEDATX = *buffer++;
+			case 37: UEDATX = *buffer++;
+			case 36: UEDATX = *buffer++;
+			case 35: UEDATX = *buffer++;
+			case 34: UEDATX = *buffer++;
+			case 33: UEDATX = *buffer++;
+			#endif
+			#if (CDC_TX_SIZE >= 32)
+			case 32: UEDATX = *buffer++;
+			case 31: UEDATX = *buffer++;
+			case 30: UEDATX = *buffer++;
+			case 29: UEDATX = *buffer++;
+			case 28: UEDATX = *buffer++;
+			case 27: UEDATX = *buffer++;
+			case 26: UEDATX = *buffer++;
+			case 25: UEDATX = *buffer++;
+			case 24: UEDATX = *buffer++;
+			case 23: UEDATX = *buffer++;
+			case 22: UEDATX = *buffer++;
+			case 21: UEDATX = *buffer++;
+			case 20: UEDATX = *buffer++;
+			case 19: UEDATX = *buffer++;
+			case 18: UEDATX = *buffer++;
+			case 17: UEDATX = *buffer++;
+			#endif
+			#if (CDC_TX_SIZE >= 16)
+			case 16: UEDATX = *buffer++;
+			case 15: UEDATX = *buffer++;
+			case 14: UEDATX = *buffer++;
+			case 13: UEDATX = *buffer++;
+			case 12: UEDATX = *buffer++;
+			case 11: UEDATX = *buffer++;
+			case 10: UEDATX = *buffer++;
+			case  9: UEDATX = *buffer++;
+			#endif
+			case  8: UEDATX = *buffer++;
+			case  7: UEDATX = *buffer++;
+			case  6: UEDATX = *buffer++;
+			case  5: UEDATX = *buffer++;
+			case  4: UEDATX = *buffer++;
+			case  3: UEDATX = *buffer++;
+			case  2: UEDATX = *buffer++;
+			default:
+			case  1: UEDATX = *buffer++;
+			case  0: break;
+		}
+		// if this completed a packet, transmit it now!
+		if (!(UEINTX & (1<<RWAL))) UEINTX = 0x3A;
+		transmit_flush_timer = TRANSMIT_FLUSH_TIMEOUT;
+	}
+	SREG = intr_state;
+	return 0;
+}
+
+
+// immediately transmit any buffered output.
+// This doesn't actually transmit the data - that is impossible!
+// USB devices only transmit when the host allows, so the best
+// we can do is release the FIFO buffer for when the host wants it
+void usb_serial_flush_output(void)
+{
+	uint8_t intr_state;
+
+	intr_state = SREG;
+	cli();
+	if (transmit_flush_timer) {
+		UENUM = CDC_TX_ENDPOINT;
+		UEINTX = 0x3A;
+		transmit_flush_timer = 0;
+	}
+	SREG = intr_state;
+}
+
+// functions to read the various async serial settings.  These
+// aren't actually used by USB at all (communication is always
+// at full USB speed), but they are set by the host so we can
+// set them properly if we're converting the USB to a real serial
+// communication
+uint32_t usb_serial_get_baud(void)
+{
+	return *(uint32_t *)cdc_line_coding;
+}
+uint8_t usb_serial_get_stopbits(void)
+{
+	return cdc_line_coding[4];
+}
+uint8_t usb_serial_get_paritytype(void)
+{
+	return cdc_line_coding[5];
+}
+uint8_t usb_serial_get_numbits(void)
+{
+	return cdc_line_coding[6];
+}
+uint8_t usb_serial_get_control(void)
+{
+	return cdc_line_rtsdtr;
+}
+// write the control signals, DCD, DSR, RI, etc
+// There is no CTS signal.  If software on the host has transmitted
+// data to you but you haven't been calling the getchar function,
+// it remains buffered (either here or on the host) and can not be
+// lost because you weren't listening at the right time, like it
+// would in real serial communication.
+// TODO: this function is untested.  Does it work?  Please email
+// paul@pjrc.com if you have tried it....
+int8_t usb_serial_set_control(uint8_t signals)
+{
+	uint8_t intr_state;
+
+	intr_state = SREG;
+	cli();
+	if (!usb_configuration) {
+		// we're not enumerated/configured
+		SREG = intr_state;
+		return -1;
+	}
+
+	UENUM = CDC_ACM_ENDPOINT;
+	if (!(UEINTX & (1<<RWAL))) {
+		// unable to write
+		// TODO; should this try to abort the previously
+		// buffered message??
+		SREG = intr_state;
+		return -1;
+	}
+	UEDATX = 0xA1;
+	UEDATX = 0x20;
+	UEDATX = 0;
+	UEDATX = 0;
+	UEDATX = 0; // TODO: should this be 1 or 0 ???
+	UEDATX = 0;
+	UEDATX = 2;
+	UEDATX = 0;
+	UEDATX = signals;
+	UEDATX = 0;
+	UEINTX = 0x3A;
+	SREG = intr_state;
+	return 0;
+}
+
+
+
+/**************************************************************************
+ *
+ *  Private Functions - not intended for general user consumption....
+ *
+ **************************************************************************/
+
+
+// USB Device Interrupt - handle all device-level events
+// the transmit buffer flushing is triggered by the start of frame
+//
+ISR(USB_GEN_vect)
+{
+	uint8_t intbits, t;
+
+        intbits = UDINT;
+        UDINT = 0;
+        if (intbits & (1<<EORSTI)) {
+		UENUM = 0;
+		UECONX = 1;
+		UECFG0X = EP_TYPE_CONTROL;
+		UECFG1X = EP_SIZE(ENDPOINT0_SIZE) | EP_SINGLE_BUFFER;
+		UEIENX = (1<<RXSTPE);
+		usb_configuration = 0;
+		cdc_line_rtsdtr = 0;
+        }
+	if (intbits & (1<<SOFI)) {
+		if (usb_configuration) {
+			t = transmit_flush_timer;
+			if (t) {
+				transmit_flush_timer = --t;
+				if (!t) {
+					UENUM = CDC_TX_ENDPOINT;
+					UEINTX = 0x3A;
+				}
+			}
+		}
+	}
+}
+
+
+// Misc functions to wait for ready and send/receive packets
+static inline void usb_wait_in_ready(void)
+{
+	while (!(UEINTX & (1<<TXINI))) ;
+}
+static inline void usb_send_in(void)
+{
+	UEINTX = ~(1<<TXINI);
+}
+static inline void usb_wait_receive_out(void)
+{
+	while (!(UEINTX & (1<<RXOUTI))) ;
+}
+static inline void usb_ack_out(void)
+{
+	UEINTX = ~(1<<RXOUTI);
+}
+
+
+
+// USB Endpoint Interrupt - endpoint 0 is handled here.  The
+// other endpoints are manipulated by the user-callable
+// functions, and the start-of-frame interrupt.
+//
+ISR(USB_COM_vect)
+{
+        uint8_t intbits;
+	const uint8_t *list;
+        const uint8_t *cfg;
+	uint8_t i, n, len, en;
+	uint8_t *p;
+	uint8_t bmRequestType;
+	uint8_t bRequest;
+	uint16_t wValue;
+	uint16_t wIndex;
+	uint16_t wLength;
+	uint16_t desc_val;
+	const uint8_t *desc_addr;
+	uint8_t	desc_length;
+
+        UENUM = 0;
+        intbits = UEINTX;
+        if (intbits & (1<<RXSTPI)) {
+                bmRequestType = UEDATX;
+                bRequest = UEDATX;
+                wValue = UEDATX;
+                wValue |= (UEDATX << 8);
+                wIndex = UEDATX;
+                wIndex |= (UEDATX << 8);
+                wLength = UEDATX;
+                wLength |= (UEDATX << 8);
+                UEINTX = ~((1<<RXSTPI) | (1<<RXOUTI) | (1<<TXINI));
+                if (bRequest == GET_DESCRIPTOR) {
+			list = (const uint8_t *)descriptor_list;
+			for (i=0; ; i++) {
+				if (i >= NUM_DESC_LIST) {
+					UECONX = (1<<STALLRQ)|(1<<EPEN);  //stall
+					return;
+				}
+				desc_val = pgm_read_word(list);
+				if (desc_val != wValue) {
+					list += sizeof(struct descriptor_list_struct);
+					continue;
+				}
+				list += 2;
+				desc_val = pgm_read_word(list);
+				if (desc_val != wIndex) {
+					list += sizeof(struct descriptor_list_struct)-2;
+					continue;
+				}
+				list += 2;
+				desc_addr = (const uint8_t *)pgm_read_word(list);
+				list += 2;
+				desc_length = pgm_read_byte(list);
+				break;
+			}
+			len = (wLength < 256) ? wLength : 255;
+			if (len > desc_length) len = desc_length;
+			do {
+				// wait for host ready for IN packet
+				do {
+					i = UEINTX;
+				} while (!(i & ((1<<TXINI)|(1<<RXOUTI))));
+				if (i & (1<<RXOUTI)) return;	// abort
+				// send IN packet
+				n = len < ENDPOINT0_SIZE ? len : ENDPOINT0_SIZE;
+				for (i = n; i; i--) {
+					UEDATX = pgm_read_byte(desc_addr++);
+				}
+				len -= n;
+				usb_send_in();
+			} while (len || n == ENDPOINT0_SIZE);
+			return;
+                }
+		if (bRequest == SET_ADDRESS) {
+			usb_send_in();
+			usb_wait_in_ready();
+			UDADDR = wValue | (1<<ADDEN);
+			return;
+		}
+		if (bRequest == SET_CONFIGURATION && bmRequestType == 0) {
+			usb_configuration = wValue;
+			cdc_line_rtsdtr = 0;
+			transmit_flush_timer = 0;
+			usb_send_in();
+			cfg = endpoint_config_table;
+			for (i=1; i<5; i++) {
+				UENUM = i;
+				en = pgm_read_byte(cfg++);
+				UECONX = en;
+				if (en) {
+					UECFG0X = pgm_read_byte(cfg++);
+					UECFG1X = pgm_read_byte(cfg++);
+				}
+			}
+        		UERST = 0x1E;
+        		UERST = 0;
+			return;
+		}
+		if (bRequest == GET_CONFIGURATION && bmRequestType == 0x80) {
+			usb_wait_in_ready();
+			UEDATX = usb_configuration;
+			usb_send_in();
+			return;
+		}
+		if (bRequest == CDC_GET_LINE_CODING && bmRequestType == 0xA1) {
+			usb_wait_in_ready();
+			p = cdc_line_coding;
+			for (i=0; i<7; i++) {
+				UEDATX = *p++;
+			}
+			usb_send_in();
+			return;
+		}
+		if (bRequest == CDC_SET_LINE_CODING && bmRequestType == 0x21) {
+			usb_wait_receive_out();
+			p = cdc_line_coding;
+			for (i=0; i<7; i++) {
+				*p++ = UEDATX;
+			}
+			usb_ack_out();
+			usb_send_in();
+			return;
+		}
+		if (bRequest == CDC_SET_CONTROL_LINE_STATE && bmRequestType == 0x21) {
+			cdc_line_rtsdtr = wValue;
+			usb_wait_in_ready();
+			usb_send_in();
+			return;
+		}
+		if (bRequest == GET_STATUS) {
+			usb_wait_in_ready();
+			i = 0;
+			#ifdef SUPPORT_ENDPOINT_HALT
+			if (bmRequestType == 0x82) {
+				UENUM = wIndex;
+				if (UECONX & (1<<STALLRQ)) i = 1;
+				UENUM = 0;
+			}
+			#endif
+			UEDATX = i;
+			UEDATX = 0;
+			usb_send_in();
+			return;
+		}
+		#ifdef SUPPORT_ENDPOINT_HALT
+		if ((bRequest == CLEAR_FEATURE || bRequest == SET_FEATURE)
+		  && bmRequestType == 0x02 && wValue == 0) {
+			i = wIndex & 0x7F;
+			if (i >= 1 && i <= MAX_ENDPOINT) {
+				usb_send_in();
+				UENUM = i;
+				if (bRequest == SET_FEATURE) {
+					UECONX = (1<<STALLRQ)|(1<<EPEN);
+				} else {
+					UECONX = (1<<STALLRQC)|(1<<RSTDT)|(1<<EPEN);
+					UERST = (1 << i);
+					UERST = 0;
+				}
+				return;
+			}
+		}
+		#endif
+        }
+	UECONX = (1<<STALLRQ) | (1<<EPEN);	// stall
+}
+
+
diff --git a/usb_serial.h b/usb_serial.h
new file mode 100644
index 0000000..14c5b1a
--- /dev/null
+++ b/usb_serial.h
@@ -0,0 +1,124 @@
+#ifndef usb_serial_h__
+#define usb_serial_h__
+
+#include <stdint.h>
+
+// setup
+void usb_init(void);			// initialize everything
+uint8_t usb_configured(void);		// is the USB port configured
+
+// receiving data
+int16_t usb_serial_getchar(void);	// receive a character (-1 if timeout/error)
+uint8_t usb_serial_available(void);	// number of bytes in receive buffer
+void usb_serial_flush_input(void);	// discard any buffered input
+
+// transmitting data
+int8_t usb_serial_putchar(uint8_t c);	// transmit a character
+int8_t usb_serial_putchar_nowait(uint8_t c);  // transmit a character, do not wait
+int8_t usb_serial_write(const uint8_t *buffer, uint16_t size); // transmit a buffer
+void usb_serial_flush_output(void);	// immediately transmit any buffered output
+
+// serial parameters
+uint32_t usb_serial_get_baud(void);	// get the baud rate
+uint8_t usb_serial_get_stopbits(void);	// get the number of stop bits
+uint8_t usb_serial_get_paritytype(void);// get the parity type
+uint8_t usb_serial_get_numbits(void);	// get the number of data bits
+uint8_t usb_serial_get_control(void);	// get the RTS and DTR signal state
+int8_t usb_serial_set_control(uint8_t signals); // set DSR, DCD, RI, etc
+
+// constants corresponding to the various serial parameters
+#define USB_SERIAL_DTR			0x01
+#define USB_SERIAL_RTS			0x02
+#define USB_SERIAL_1_STOP		0
+#define USB_SERIAL_1_5_STOP		1
+#define USB_SERIAL_2_STOP		2
+#define USB_SERIAL_PARITY_NONE		0
+#define USB_SERIAL_PARITY_ODD		1
+#define USB_SERIAL_PARITY_EVEN		2
+#define USB_SERIAL_PARITY_MARK		3
+#define USB_SERIAL_PARITY_SPACE		4
+#define USB_SERIAL_DCD			0x01
+#define USB_SERIAL_DSR			0x02
+#define USB_SERIAL_BREAK		0x04
+#define USB_SERIAL_RI			0x08
+#define USB_SERIAL_FRAME_ERR		0x10
+#define USB_SERIAL_PARITY_ERR		0x20
+#define USB_SERIAL_OVERRUN_ERR		0x40
+
+// This file does not include the HID debug functions, so these empty
+// macros replace them with nothing, so users can compile code that
+// has calls to these functions.
+#define usb_debug_putchar(c)
+#define usb_debug_flush_output()
+
+
+
+// Everything below this point is only intended for usb_serial.c
+#ifdef USB_SERIAL_PRIVATE_INCLUDE
+#include <avr/io.h>
+#include <avr/pgmspace.h>
+#include <avr/interrupt.h>
+
+#define EP_TYPE_CONTROL			0x00
+#define EP_TYPE_BULK_IN			0x81
+#define EP_TYPE_BULK_OUT		0x80
+#define EP_TYPE_INTERRUPT_IN		0xC1
+#define EP_TYPE_INTERRUPT_OUT		0xC0
+#define EP_TYPE_ISOCHRONOUS_IN		0x41
+#define EP_TYPE_ISOCHRONOUS_OUT		0x40
+#define EP_SINGLE_BUFFER		0x02
+#define EP_DOUBLE_BUFFER		0x06
+#define EP_SIZE(s)	((s) == 64 ? 0x30 :	\
+			((s) == 32 ? 0x20 :	\
+			((s) == 16 ? 0x10 :	\
+			             0x00)))
+
+#define MAX_ENDPOINT		4
+
+#define LSB(n) (n & 255)
+#define MSB(n) ((n >> 8) & 255)
+
+#if defined(__AVR_AT90USB162__)
+#define HW_CONFIG() 
+#define PLL_CONFIG() (PLLCSR = ((1<<PLLE)|(1<<PLLP0)))
+#define USB_CONFIG() (USBCON = (1<<USBE))
+#define USB_FREEZE() (USBCON = ((1<<USBE)|(1<<FRZCLK)))
+#elif defined(__AVR_ATmega32U4__)
+#define HW_CONFIG() (UHWCON = 0x01)
+#define PLL_CONFIG() (PLLCSR = 0x12)
+#define USB_CONFIG() (USBCON = ((1<<USBE)|(1<<OTGPADE)))
+#define USB_FREEZE() (USBCON = ((1<<USBE)|(1<<FRZCLK)))
+#elif defined(__AVR_AT90USB646__)
+#define HW_CONFIG() (UHWCON = 0x81)
+#define PLL_CONFIG() (PLLCSR = 0x1A)
+#define USB_CONFIG() (USBCON = ((1<<USBE)|(1<<OTGPADE)))
+#define USB_FREEZE() (USBCON = ((1<<USBE)|(1<<FRZCLK)))
+#elif defined(__AVR_AT90USB1286__)
+#define HW_CONFIG() (UHWCON = 0x81)
+#define PLL_CONFIG() (PLLCSR = 0x16)
+#define USB_CONFIG() (USBCON = ((1<<USBE)|(1<<OTGPADE)))
+#define USB_FREEZE() (USBCON = ((1<<USBE)|(1<<FRZCLK)))
+#endif
+
+// standard control endpoint request types
+#define GET_STATUS			0
+#define CLEAR_FEATURE			1
+#define SET_FEATURE			3
+#define SET_ADDRESS			5
+#define GET_DESCRIPTOR			6
+#define GET_CONFIGURATION		8
+#define SET_CONFIGURATION		9
+#define GET_INTERFACE			10
+#define SET_INTERFACE			11
+// HID (human interface device)
+#define HID_GET_REPORT			1
+#define HID_GET_PROTOCOL		3
+#define HID_SET_REPORT			9
+#define HID_SET_IDLE			10
+#define HID_SET_PROTOCOL		11
+// CDC (communication class device)
+#define CDC_SET_LINE_CODING		0x20
+#define CDC_GET_LINE_CODING		0x21
+#define CDC_SET_CONTROL_LINE_STATE	0x22
+#endif
+#endif