Only thing I see that may be missing is a serial monitor.
Works great on the Nexus 7 to an Arduino Uno R3 (needs OTG USB adapter) - but I sure would like to see debugging messages.
Or can I do that with ArduinoCommander?

Let me refer you again to the PIC datasheet....  Rx and Tx are USART pins unrelated to the SPI library provided by Arduino, and I don't think you will get that to work. SPI is designed in the PIC for in-circuit programming; you can have a PIC soldered in a circuit and still read/reprogram it. The Arduino is the Master and the PIC is the Slave. The Arduino SPI library combined with the programming details in the datasheet give you everything you need.

Robert

Let me refer you to the PIC 16F689 datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/41262E.pdf

The SPI interface can be used to both read and write program and EEROM memories. Code memory is under flag protection; if this was not set when the PIC was programmed, you can read it like any other memory. It is very handy to read program memory, edit it, and write it back.

Microchip really dropped the ball on microprocessors - they had the field to themselves, but made the cost of entry way to high for individual users.  Expensive development systems, expensive compilers, etc.  All the things Arduino did right.

Robert

Thanks so much for doing this library - it works great!

I did get hung up on the print function not allowing String, so I added an overload:

void GLCD::print(String st, byte x, byte y, byte r, byte g, byte b)
{
  int stl, i;
  
  stl = st.length();
  if (x==RIGHT)
        x=128-(stl*6);
  if (x==CENTER)
        x=(128-(stl*6))/2;
  
  for (i=0; i<stl; i++)
    printChar(st.charAt(i), x + (i*6), y, r, g, b);
}

If this is useful to anyone, just add this after the print definition in the library code - and add a corresponding header line.

Robert