Porting Libraries for the Spark Core

This repo includes a (work in progress) how-to on porting non-Spark C/C++ (Arduino, Teensy, etc) libraries to the SparkCore and a list of ported libraries.

Contributing

If you'd like to contribute to either the how-to or the library list feel free to either

• Fork this repo, make changes, and issue a pull request
• Submit an issue and I'll try to get on it asap!

Library List

The library list can be found here

Porting Arduino Libraries

Making #include "Arduino.h" portable

Common Problems

WProgram.h: No such file or directory

Arduino.h: No such file or directory

Solution

Arduino.h (WProgram.h in older Arduino IDE versions) defines functions like digitalRead, digitalWrite, etc. The SparkCore has it's own version of this header file. Instead of "Arduino.h" you want to use "application.h". However instead of just replacing the filename you can make the library backwards compatible with just a few lines of code!

To achieve this you need to replace the following line(s) in all .h files in your library.

Replace:

#include "Arduino.h"

or

#if defined(ARDUINO) && ARDUINO >= 100
  #include "Arduino.h"	// for digitalRead, digitalWrite, etc
#else
  #include "WProgram.h"
#endif

with

#if defined (SPARK)
  #include "application.h"
#else
  #if defined(ARDUINO) && ARDUINO >= 100
    #include "Arduino.h"
  #else
    #include "WProgram.h"
  #endif
  // here could follow some of the includes only needed on Arduino
  // see bellow
  
#endif

Some libraries that need including on Arduino, are already "pre-included" via application.h

So for example

EEPROM.h
SPI.h
WiFi.h
Wire.h
...

Getting the User LED to work

Common Problems

The user LED doesn't light up!

Solution

The SparkCore has a different pin connected to the on-board user LED. Instead of pin D13 (on Arduino) it uses D7. Assuming your library uses something like this to define the user LED pin:

#define ledPin D13

simply change it to

#define ledPin D7

Pgmspace Issues

Common Problems

pgmspace.h: No such file or directory

Solution

Because the microcontroller at the heart of an Arduino, an AVR, has separate program memory and data memory spaces there are special functions to read and write these memory spaces. On the SparkCore's microcontroller, a STM32, there is no need for those same functions because the memory space is unified.

To fix replace:

#include <avr/pgmspace.h>

with

#ifdef __AVR__
#include <avr/pgmspace.h>
#else
#define pgm_read_byte(addr) (*(const unsigned char *)(addr))
#define pgm_read_byte_near(addr) (*(const unsigned char *)(addr))
#define pgm_read_word(addr) (*(const unsigned short *)(addr))
#define pgm_read_word_near(addr) (*(const unsigned short *)(addr))
#endif

Notes

This will not fix libraries which need to WRITE to flash memory.

F Macro is Undefined

Common Problem

The F() macro in Arduino-land places string between the ( and ) into flash memory. Such a macro doesn't exist in the Spark IDE

Solution

Include

#define F(x) ((const char*)(x))

at the top of your main .h or .ino file

More to come!

Special thanks to:

• peekay123
• ScruffR