Add printf to source files

[blhough]

printf doesn't work by default for some reason. You must modify the source code included in the teensy library.

follow instructions here: http://playground.arduino.cc/Main/Printf#sourceblock1

Summary: In directory: {installdir)/hardware/teensy/cores/teensy3/

comment out lines 87-107 in Print.cpp

comment out lines 98 and 99 in Print.h paste this code below

#include <stdarg.h>
#define PRINTF_BUF 200 // define the tmp buffer size (change if desired)
int printf(const char *format, ...)
{
    char buf[PRINTF_BUF];
    va_list ap;
    va_start(ap, format);
    int  n = vsnprintf(buf, sizeof(buf), format, ap);
    for (char *p = &buf[0]; *p; p++) // emulate cooked mode for newlines
    {
        if (*p == '\n')
            write('\r');
        write(*p);
    }
    va_end(ap);
    return n;
}
#ifdef F // check to see if F() macro is available
int printf(const __FlashStringHelper *format, ...)
{
    char buf[PRINTF_BUF];
    va_list ap;
    va_start(ap, format);
#ifdef __AVR__k
    int n = vsnprintf_P(buf, sizeof(buf), (const char *)format, ap); // progmem for AVR
#else
    int n = vsnprintf(buf, sizeof(buf), (const char *)format, ap); // for the rest of the world
#endif
    for (char *p = &buf[0]; *p; p++) // emulate cooked mode for newlines
    {
        if (*p == '\n')
            write('\r');
        write(*p);
    }
    va_end(ap);
    return n;
}
#endif

I don't know an easy way to make this part of our project code