File content as of revision 1:dd1d1b64b9a5:

#include "mbed.h"
#include "Adafruit_LEDBackpack.h"
#include "Adafruit_GFX.h"
 
I2C i2c(D14, D15);

//mpl - something with stdio screwing things up.  need to define serial port to use for debug
Serial pc (USBTX,USBRX);

Adafruit_16x8matrix matrix = Adafruit_16x8matrix(&i2c);
Adafruit_16x8matrix matrix2 = Adafruit_16x8matrix(&i2c); 

void scrollText(char * buffer, uint8_t buf_len);

int main() {

/*    matrix[0].begin(0x70);
    //while(1) 
//    {
        matrix[0].clear();
        for (int i = 0; i < 16; i++) {
          for (int j = 0; j < 8; j++) {
              matrix.drawPixel(i, j, LED_ON);  
              matrix.writeDisplay();  // write the changes we just made to the display
              Thread::wait(10);
          }
        }

        matrix2.begin(0x71);
        matrix2.clear();

        for (int i = 0; i < 16; i++) {
          for (int j = 0; j < 8; j++) {
              matrix2.drawPixel(i, j, LED_ON);  
              matrix2.writeDisplay();  // write the changes we just made to the display
              Thread::wait(10);
          }
        }
        
*/
        matrix2.begin(0x71);
        matrix2.clear();
        matrix2.writeDisplay();
//        matrix2.writeChar('A');
//       matrix2.writeDisplay();
//        Thread::wait(10);

        matrix.begin(0x70);
        matrix.clear();
        matrix.writeDisplay();
//        matrix.writeChar('A');
//        matrix.writeChar('B');
//        matrix.writeChar('C');                
//        matrix.writeDisplay();
        
         char buffer [50];
         sprintf (buffer, "Hello\0");
        scrollText(buffer,strlen(buffer));

//    }
}

void scrollText(char * buffer, uint8_t buf_len)
{
    uint8_t x_pos;
    uint8_t m;
    char c;
    
    //pc.printf("buffer = %s, len = %d\r\n", buffer, buf_len);

    //Need to start at the end and draw backwards, each time scrolling one pixel to the right
    // then, stop when get to first character.      
    //find example
    
    /* code inspired by LOLShield library */
    int xoff=31;/* set offset to the right end of the screen*/
    for(int i=0; i<buf_len*5 +52; i++){ /*scrolling loop*/
        for(int j=0; j<buf_len; j++){ /*loop over all of the chars in the text*/
            if(xoff + j*6 <32)
            {
                matrix.drawChar(xoff + j*6, 0, buffer[j], 1, 0, 1);
                matrix.writeDisplay();
            }else
            {
                matrix2.drawChar(xoff + j*6-32, 0, buffer[j], 1, 0, 1);
                matrix2.writeDisplay();
            }    
        }
        xoff--; /* decrement x offset*/
        Thread::wait(70);
        matrix.clear();
        matrix2.clear();
    }

    
}