Emulino is an emulator for the Arduino platform by Greg Hewgill, originally found on [[http://hewgill.com/journal/entries/507-emulino-arduino-cpu-emulator|emulino: arduino cpu emulator]].

With it, you can build ("Verify") a .pde sketch in [[http://www.arduino.cc/en/Main/Software|Arduino IDE]] which uses serial port for communication to say a .hex file, and then you can invoke the emulino executable with the .hex file as an argument, and get a local simulation of how an Arduino would behave; useful for debugging without wasting burn cycles on the Arduino's AVR chip. 


== Installation ==

Here is a brief overview of steps to get emulino built in Ubuntu 10.04 Lucid: 

{{{
sudo apt-get install git # to check out the source
sudo apt-get install scons # to build the source
git clone git://github.com/ghewgill/emulino.git
cd emulino/
which python # see what your python executable is 
nano SConstruct # replace '/opt/local/bin/python2.5' with your python executable
scons # build
}}}

The result is an executable (which is also posted on http://sourceforge.net/projects/sdaaubckp/files/emulino/10.04/emulino/download); the executable also works on 9.04. 


== Usage ==

For instance, one could use the following simple code, which simply increases a counter and writes its value on serial, as test.pde in Arduino IDE: 
{{{
int counter = 0;

void setup()
{
	// initiate Arduino serial communication
	Serial.begin(115200);
}

void loop()
{
  counter = counter + 1;
  Serial.print("Counter: ");
  Serial.print(counter, DEC);
  Serial.println(); 
  //delay(50);
}
}}} 

By clicking on "Verify", the code is built - and [[http://www.arduino.cc/en/Hacking/BuildProcess|during a "Verify" the .hex file is written to /tmp]]. In order to simulate the code, one can simply call emulino with the path to the hex file as argument: 

{{{
$ ./emulino /tmp/build523158875647966391.tmp/test.cpp.hex 
emulino: Loading hex image: /tmp/build523158875647966391.tmp/test.cpp.hex
Counter: 1
Counter: 2
Counter: 3
Counter: 4
...
}}}

=== Serial-'std' in-out ===

Note that, in principle, `emulino` uses `stdin` and `stdout` of the console to simulate serial input/output. There is a command switch "`-io`" which should allow input/output to/from files (which have fixed names of `name-of-hexfile.hex.in` and `name-of-hexfile.hex.out`), however I cannot get it to work every time (maybe instead of files, one should use `mknod` and named pipes; not sure). 

Note however the example below - which reads a character from serial and echoes it back to serial: 

{{{
static unsigned char _c; 

void setup() 
{
  Serial.begin(9600); 
} 

void loop() 
{

  // read in a byte, and send it back immediately 
  
  	// send data only when you receive data: 
	if (Serial.available() > 0) {
		// read the incoming byte:
		_c = Serial.read();

		// say what you got:
                Serial.print(_c);  
	}
        
        // must have delay for emulino to work
        delay(1);

}
}}}

In this example, if the delay statement is missing, then `emulino` will never register that a character came in from "serial"; with the delay statement, a command like session will look like: 
{{{
$ stty -icanon ; ./emulino /tmp/buildXXX.tmp/test.cpp.hex
emulino: Loading hex image: /tmp/buildXXX.tmp/test.cpp.hex
tteessttiinngg  bbuuttttoonn  pprreessss^C

}}}

Note again that "`stty -icanon`" seems to be needed, in order to set up the ''terminal'' as a character device - so that keypresses are passed on to "stdin" per individual character basis.